Apex Trigger Error: RECORD TYPE UPDATE: System.NullPointerException: Attempt to de-reference a null object

Hi,

I am getting an error message with a trigger on case. Cant figure what I am doing wrong.

Thanks in advance for any help with this.

Scenario: Apex Trigger to update record type based on TYPE value on a case. Fetching record type ID where record type name is 'SR'

Error on Save:  

Error:Apex trigger Case_Record_Type_Update caused an unexpected exception, contact your administrator: Case_Record_Type_Update: execution of BeforeUpdate caused by: System.NullPointerException: Attempt to de-reference a null object: Trigger.Case_Record_Type_Update: line 22, column 34

I have tried with some changes in the below code but same error each time.

CODE:

   for (Case cs : Trigger.new) {

          Schema.DescribeSObjectResult DSOR = Schema.SObjectType.Case;          

           if (cs.Status == 'Accept' | cs.Status == 'Disregard') {

             cs.Subject = 'Accept/Disregard';

             Id NewRecordTypeforCase = rtByName.getRecordTypeId(); <--- ERROR LINE

             cs.RecordTypeId = NewRecordTypeforCase;

         } // End If Accept/Disregard

      } // End If Service Request

    } // End If Not NUll check

  } // End For Loop on Case

} // End Trigger Block

DEBUG LOG:

*** Beginning SetAssetAccount on Case trigger event BeforeUpdate for 500T0000001fVim

20090902190242.983:Trigger.SetAssetAccount: line 8, column 2: SelectLoop:LIST:SOBJECT:Case
20090902190242.983:Trigger.SetAssetAccount: line 18, column 2: >>>>>Changed Asset IDs: {}

Cumulative resource usage:

Resource usage for namespace: (default)
Number of SOQL queries: 0 out of 20
Number of query rows: 0 out of 1000
Number of SOSL queries: 0 out of 0
Number of DML statements: 0 out of 20
Number of DML rows: 0 out of 100
Number of script statements: 6 out of 10200
Maximum heap size: 0 out of 200000
Number of callouts: 0 out of 10
Number of Email Invocations: 0 out of 10
Number of fields describes: 0 out of 10
Number of record type describes: 0 out of 10
Number of child relationships describes: 0 out of 10
Number of picklist describes: 0 out of 10
Number of future calls: 0 out of 10
Number of find similar calls: 0 out of 0
Number of System.runAs() invocations: 0 out of 0

Total email recipients queued to be sent : 0
Static variables and sizes:
SetAssetAccount:assetIds:4
SetAssetAccount:idx:4


*** Ending SetAssetAccount on Case trigger event BeforeUpdate for 500T0000001fVim

*** Beginning Case_Record_Type_Update on Case trigger event BeforeUpdate for 500T0000001fVim

20090902190242.991:Trigger.Case_Record_Type_Update: line 2, column 2: SelectLoop:LIST:SOBJECT:Case
System.NullPointerException: Attempt to de-reference a null object

Trigger.Case_Record_Type_Update: line 22, column 34


Cumulative resource usage:

Resource usage for namespace: (default)
Number of SOQL queries: 0 out of 20
Number of query rows: 0 out of 1000
Number of SOSL queries: 0 out of 0
Number of DML statements: 0 out of 20
Number of DML rows: 0 out of 100
Number of script statements: 11 out of 10200
Maximum heap size: 0 out of 200000
Number of callouts: 0 out of 10
Number of Email Invocations: 0 out of 10
Number of fields describes: 0 out of 10
Number of record type describes: 1 out of 10
Number of child relationships describes: 0 out of 10
Number of picklist describes: 0 out of 10
Number of future calls: 0 out of 10
Number of find similar calls: 0 out of 0
Number of System.runAs() invocations: 0 out of 0

Total email recipients queued to be sent : 0
Stack frame variables and sizes:
  Frame0
    rtByName:0
    rtMapByName:326
    cs:0
    DSOR:153


*** Ending Case_Record_Type_Update on Case trigger event BeforeUpdate for 500T0000001fVim

thanks

Prashant

Edit 1 and 2: Added intend on Code snippet.