I have been all over, and I don't understand.  What is it asking for, parent ID of what?  What am I missing here.  Thank you.
My code is as follows:

global class BatchSyncErrors implements Database.Batchable<sOBject>, Database.Stateful{
   
    global string excelHeader = 'ApexClassID,  CompletedDate ,  ExtendedStatus,  JobItemsProcessed,  JobType,  MethodName,  NumberOfErrors,  Status,  TotalJobItems \n';
    global string finalstr = '';
    
    //constructor
    global BatchSyncErrors(){
        finalstr = excelHeader;
    }
    //start method
    global Database.QueryLocator start(Database.BatchableContext BC){
        return Database.getQueryLocator('SELECT ApexClassID, CompletedDate, ExtendedStatus, JobItemsProcessed, JobType, MethodName, NumberOfErrors, Status, TotalJobItems FROM AsyncApexJob Limit 10');
    }
 
    //execute
        global void execute(Database.BatchableContext BC, List<sOBject> scope){

            string recordString;
        
            for(sOBject a: scope){
        
                // Type Cast sOBject to AsyncApexJob
                AsyncApexJob asyncApexJobRecord = (AsyncApexJob) a;
                   
                if(recordString == NULL){
                    recordString = AsyncApexJobRecord.ApexClassID +',' + AsyncApexJobRecord.CompletedDate +','+ AsyncApexJobRecord.ExtendedStatus+',' + AsyncApexJobRecord.JobItemsProcessed + ',' + AsyncApexJobRecord.JobType +  ',' + AsyncApexJobRecord.MethodName + ',' + AsyncApexJobRecord.NumberOfErrors + ',' + AsyncApexJobRecord.TotalJobItems + ','+ AsyncApexJobRecord.JobItemsProcessed + ',' +AsyncApexJobRecord.JobType + ',' + AsyncApexJobRecord.TotalJobItems+ '\n';
                } else {
                    recordString += AsyncApexJobRecord.ApexClassID +',' + AsyncApexJobRecord.CompletedDate +','+ AsyncApexJobRecord.ExtendedStatus+',' + AsyncApexJobRecord.JobItemsProcessed + ',' + AsyncApexJobRecord.JobType +  ',' + AsyncApexJobRecord.MethodName + ',' + AsyncApexJobRecord.NumberOfErrors + ',' + AsyncApexJobRecord.TotalJobItems + ','+ AsyncApexJobRecord.JobItemsProcessed + ',' +AsyncApexJobRecord.JobType + ',' + AsyncApexJobRecord.TotalJobItems+ '\n';
                }
        
            }
        
            finalstr += recordString;

}

    
    //finish
    global void finish (Database.BatchableContext BC){
       
        system.debug('**** Final String *** ' + finalstr);
        //TODO: pass this string to create CSV in your CSV Method.
            String csvContent = finalstr;
                Attachment attachment = new Attachment();
                attachment.Body = Blob.valueOf(csvContent);
                attachment.Name = 'csvFile.csv';
              
                insert attachment;
       
         //TODO: Create an generic method to send emails & pass this attachment.
         
        AsyncApexJob a = [SELECT Id, Status, NumberOfErrors, JobItemsProcessed, TotalJobItems, CreatedBy.Email,ExtendedStatus,JobType,ApexClassId,MethodName
      FROM AsyncApexJob WHERE Id =
      :BC.getJobId()];
            
        Messaging.Singleemailmessage mail = new Messaging.Singleemailmessage();
            mail.setToAddresses((new String[] {'test@test.com'}));
            //mail.setReplyTo('noreply@privatebudget.com');
            mail.setSenderDisplayName('Batch Class Errors');
            mail.setSubject('Batch Class Errors');
            mail.setBccSender(false);
            mail.setUseSignature(false);
            mail.setPlainTextBody(finalstr);
            system.debug('@@@@ sendEmail - mail : ' + mail);
            Messaging.sendEmail(new Messaging.SingleEmailMessage[] { mail });
 
    }
}


and the email received is:


Apex script unhandled exception by user/organization: 00518000001WfNj/00D180000008oBS
Source organization: 00D300000006IaD (null)
Failed to process batch for class 'BatchSyncErrors' for job id '7071800000gWEFg'

caused by: System.DmlException: Insert failed. First exception on row 0; first error: REQUIRED_FIELD_MISSING, Required fields are missing: [ParentId]: [ParentId]

Class.BatchSyncErrors.finish: line 48, column 1

Debug Log:
40.0 APEX_CODE,DEBUG;APEX_PROFILING,FINEST;CALLOUT,FINEST;DB,FINEST;SYSTEM,FINE;VALIDATION,INFO;VISUALFORCE,FINER;WAVE,FINEST;WORKFLOW,FINER
15:56:02.0 (258843)|USER_INFO|[EXTERNAL]|00518000001WfNj|all60388@adobe.com.signstage|Pacific Standard Time|GMT-07:00
15:56:02.0 (290487)|EXECUTION_STARTED
15:56:02.0 (294740)|CODE_UNIT_STARTED|[EXTERNAL]|01p18000000BBrV|BatchSyncErrors
15:56:02.0 (11144677)|SYSTEM_METHOD_ENTRY|[41]|System.debug(ANY)
15:56:02.0 (11171785)|USER_DEBUG|[41]|DEBUG|**** Final String *** ApexClassID,  CompletedDate ,  ExtendedStatus,  JobItemsProcessed,  JobType,  MethodName,  NumberOfErrors,  Status,  TotalJobItems 
01p18000000BBrVAAW,2017-09-08 17:16:32,null,1,BatchApex,null,0,1,1,BatchApex,1
null,null,null,0,ApexToken,null,0,0,0,ApexToken,0
01p1800000062WPAAY,2017-09-07 15:20:29,null,1,BatchApex,null,0,1,1,BatchApex,1
null,null,null,0,ApexToken,null,0,0,0,ApexToken,0
null,null,null,0,ApexToken,null,0,0,0,ApexToken,0
01p180000005zyLAAQ,2017-09-03 06:00:26,null,1,BatchApex,null,0,1,1,BatchApex,1
01p180000005zyLAAQ,2017-09-03 06:00:17,null,1,BatchApexWorker,null,0,1,1,BatchApexWorker,1
01p18000000BBrVAAW,2017-09-07 20:51:59,null,1,BatchApex,null,0,1,1,BatchApex,1
null,null,null,0,ApexToken,null,0,0,0,ApexToken,0
01p18000000BBrVAAW,2017-09-07 19:46:50,null,1,BatchApex,null,0,1,1,BatchApex,1

15:56:02.0 (11190603)|SYSTEM_METHOD_EXIT|[41]|System.debug(ANY)
15:56:02.0 (11352022)|SYSTEM_METHOD_ENTRY|[45]|Blob.valueOf(String)
15:56:02.0 (11392106)|SYSTEM_METHOD_EXIT|[45]|Blob.valueOf(String)
15:56:02.0 (11548575)|DML_BEGIN|[48]|Op:Insert|Type:Attachment|Rows:1
15:56:02.0 (11562050)|LIMIT_USAGE|[48]|DML|1|150
15:56:02.0 (11575389)|LIMIT_USAGE|[48]|DML_ROWS|1|10000
15:56:02.0 (425072145)|CODE_UNIT_STARTED|[EXTERNAL]|01q40000000Td0s|AttachmentTrigger on Attachment trigger event BeforeInsert for [new]
15:56:02.0 (425366692)|SYSTEM_METHOD_ENTRY|[13]|Limit.getLimitQueries()
15:56:02.0 (425414605)|SYSTEM_METHOD_EXIT|[13]|Limit.getLimitQueries()
15:56:02.0 (425428037)|SYSTEM_METHOD_ENTRY|[13]|Limit.getQueries()
15:56:02.0 (425434866)|SYSTEM_METHOD_EXIT|[13]|Limit.getQueries()
15:56:02.0 (425440962)|SYSTEM_METHOD_ENTRY|[13]|Limit.getLimitDmlRows()
15:56:02.0 (425445832)|SYSTEM_METHOD_EXIT|[13]|Limit.getLimitDmlRows()
15:56:02.0 (425451753)|SYSTEM_METHOD_ENTRY|[13]|Limit.getDmlRows()
15:56:02.0 (425455759)|SYSTEM_METHOD_EXIT|[13]|Limit.getDmlRows()
15:56:02.458 (458339540)|CUMULATIVE_LIMIT_USAGE
15:56:02.458 (458339540)|LIMIT_USAGE_FOR_NS|(default)|
  Number of SOQL queries: 0 out of 200
  Number of query rows: 0 out of 50000
  Number of SOSL queries: 0 out of 20
  Number of DML statements: 1 out of 150
  Number of DML rows: 1 out of 10000
  Maximum CPU time: 0 out of 60000
  Maximum heap size: 0 out of 12000000
  Number of callouts: 0 out of 0
  Number of Email Invocations: 0 out of 10
  Number of future calls: 0 out of 0
  Number of queueable jobs added to the queue: 0 out of 1
  Number of Mobile Apex push calls: 0 out of 10

15:56:02.458 (458339540)|TOTAL_EMAIL_RECIPIENTS_QUEUED|0
15:56:02.458 (458339540)|STATIC_VARIABLE_LIST|
  char[]:DigitTens:0
  long:serialVersionUID:0
  long:serialVersionUID:0
  String:_sfdcAdditionalCodeLocations:0
  String:__sfdcParameterizedTypes:0
  double:MAX_VALUE:0
  Boolean:FALSE:0
  long:serialVersionUID:0
  String:_sfdcSuppressedCodeLocations:0
  double:MIN_VALUE:0
  int:SIZE:0
  double:NEGATIVE_INFINITY:0
  int:MAX_VALUE:0
  String:_sfdcAdditionalCodeLocations:0
  char[]:digits:0
  double:NaN:0
  Boolean:TRUE:0
  String:_sfdcAdditionalCodeLocations:0
  int:MIN_VALUE:0
  char[]:DigitOnes:0
  String:_sfdcAdditionalCodeLocations:0
  int:BYTES:0
  int:MIN_EXPONENT:0
  int[]:sizeTable:0
  int:MAX_EXPONENT:0
  int:SIZE:0
  double:POSITIVE_INFINITY:0
  double:MIN_NORMAL:0
  int:BYTES:0

15:56:02.458 (458339540)|CUMULATIVE_LIMIT_USAGE_END

15:56:02.0 (459420821)|CODE_UNIT_FINISHED|AttachmentTrigger on Attachment trigger event BeforeInsert for [new]
15:56:02.0 (470961184)|DML_END|[48]
15:56:02.0 (471029439)|EXCEPTION_THROWN|[48]|System.DmlException: Insert failed. First exception on row 0; first error: REQUIRED_FIELD_MISSING, Required fields are missing: [ParentId]: [ParentId]
15:56:02.0 (471405705)|FATAL_ERROR|System.DmlException: Insert failed. First exception on row 0; first error: REQUIRED_FIELD_MISSING, Required fields are missing: [ParentId]: [ParentId]

Class.BatchSyncErrors.finish: line 48, column 1
15:56:02.531 (531444350)|CUMULATIVE_PROFILING_BEGIN
15:56:02.531 (531444350)|CUMULATIVE_PROFILING|No profiling information for SOQL operations
15:56:02.531 (531444350)|CUMULATIVE_PROFILING|No profiling information for SOSL operations
15:56:02.531 (531444350)|CUMULATIVE_PROFILING|DML operations|
Class.BatchSyncErrors.finish: line 48, column 1: Insert: Attachment: executed 1 time in 460 ms

15:56:02.531 (531444350)|CUMULATIVE_PROFILING|method invocations|
External entry point: global void finish(Database.BatchableContext): executed 1 time in 460 ms
External entry point: public void invoke(): executed 1 time in 33 ms
Class.AttachmentTriggerHandler.executeOperations: line 19, column 1: private static void onBeforeInsert(List<Attachment>): executed 1 time in 0 ms
Class.BatchSyncErrors.finish: line 41, column 1: global public static void debug(ANY): executed 1 time in 0 ms
Class.BatchSyncErrors.finish: line 45, column 1: public static Blob valueOf(String): executed 1 time in 0 ms
Trigger.AttachmentTrigger: line 13, column 1: global public static Integer getLimitQueries(): executed 4 times in 0 ms
Trigger.AttachmentTrigger: line 14, column 1: public static void executeOperations(List<Attachment>, List<Attachment>, Map<Id,Attachment>, Map<Id,Attachment>, Boolean, Boolean, Boolean, Boolean, Boolean, Boolean, Boolean): executed 1 time in 0 ms

15:56:02.531 (531444350)|CUMULATIVE_PROFILING_END