I would try debugging the component interface from PeopleCode. To accomplish that you need to modify a delivered function. The function is located at FUNCLIB_CI.CI_EXCEPTIONS FieldFormula and is called ciCreateExceptionEntry

Right after the following code

If All(&MsgSetNbr, &MsgNbr) Then
&ExceptionRec.MSG_SEVERITY.Value = ciGetSeverity(&MsgSetNbr, &MsgNbr);
End-If;

add this:

MessageBox(0, "", 0, 0, "Error Message: " | &ExceptionRec.MESSAGE_TEXT.Value);

Now when a CI is called and an error occurs you will get a messagebox on the screen indicating the error. Hopefully this will give you a more meaningful error.