I have migrated the application from 1.5 to 2.0 and the proejct compiled sucessfully however when I open the viewer I am getting an exception ..  Has any one seen this exception before and how to resolve this ? 

System.ArgumentException was unhandled
  Message="An item with the same key has already been added."
  Source="mscorlib"
  StackTrace:
       at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
       at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
       at System.Collections.Generic.Dictionary`2.System.Collections.Generic.ICollection>.Add(KeyValuePair`2 keyValuePair)