I'm presuming you have an ActiveXScript task like
Function Main()
DestinationColum("Col001") = Source("Col001")
etc...
If you put the On Error Resume Next statement before the line you want to capture error information for, then you can get error information via the VBScript Err object.
Once you've caught the error, you should also turn off the error handling using On Error Goto 0
Generally what I have is something like the following,
On Error Resume Next
' my VBScript statement that might error
iErrNum = Err.Number
iErrDesc = Err.Description
On Error Goto 0
If iErrNum <> 0 Then
' my error handling reporting bits
End If
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Colt 45 - the original point and click interface