Since this morning (8 AM Eastern) I'm getting random errors in various apps that read/write to Salesforce (na3 specifically).  These errors are apparently from the XML and .NET treats them differently in various scenarios.  As of right now I've changed our main middle layer's API from 17 to 16 and that allowed events and opportunities to be read from and written to.  But now it looks like task creation is failing, and that works all day everyday.  Is it possible that we're the only org having this problem today?  I don't get it...  

here's pert of an error email:

Date: 2/15/2010 1:54:58 PMType: CSG.Exceptions.CSGExceptionAssembly: CSG.Salesforce.sObjects.Task, MiddleTier, Version=1.5.9.0, Culture=neutral, PublicKeyToken=nullCodebase: file:///C:/XXXXXX/MiddleTier.DLLMessage: There is an error in XML document (1, 672).Source: MiddleTierStacktrace: at CSG.Salesforce.sObjects.Task.CreateUserTask(String SalesforceID, String Subject, String Comments, DateTime DueDate, Uri TaskURL, String Priority, String Status) at CSG.Salesforce.sObjects.Task.CreateUserTask(String SalesforceID, String Subject, String Comments, DateTime DueDate, String eFolderID, String Priority, String Status) at CSG.Salesforce.Functions.CreateUserTask(String SalesforceID, String Subject, String Comments, DateTime DueDate, String eFolderID, String Priority, String Status) at CSG.MSI.Fulfillments.Fulfillments.CreateScrubTask(String eFolderID, String Subject, String Comments, DateTime DueDate)Exception Custom Data: eFolderID = 0000000000000000000000000029166 Subject = Letter Scrubbing Comments = There are 291 records to be scrubbed today DueDate = 2/15/2010 1:54:55 PM

 Any insight would be helpful.