By the sounds of it, the problem is most likely as Larry Long and Marcia Akins suggested, an alias being refered to in the structure of DataDict. Check the index expressions for the CurrUser alias. If it's not there then try the default values.

If you still haven't located it, then it may be in a proc in a UDF or the stored procedures. If you have any procs that perform database utilities -- like a NewID() function for generating a unique id, or a CheckRule() function that validates the user's input -- and those procs are used in the Rule or Default Value parts of the table structure, and those procs refer to CurrUser alias, then the CurrUser alias must be available.

I hope I explained that right :-)