Vista - MS Access 2003 & VISTA

I have a MS Access database which I've developed using MS Access 2003 on an XP Machine. It has a Front-End which I give to each user and a single Back End database (Jet Database, not SQL Server). I have some users on XP with Access 2003 and others on VISTA with Access 2007. I have one user on VISTA with Access 2003.

This problem occurs ONLY on the one user system running on VISTA and Access 2003. And it ONLY occurs in my production database.

I have a zip code field in my database which is 9 characters long. For reports, I check if the 6th character is numeric using an IIF stmt. If numeric, then I print the left 5 characters, a dash, then the 6-10th characters. Otherwise, I just print the zip with no additional editing or formatting.

Everywhere I print the zip code, or city/state/zip, or street address/city/state/zip, my user gets an error (only this one user - everyone else can view the information on the report just fine).

I was including the concatention of the city, state, and Zip - along with the IsNumeric check on the 6th zip character all in one field. The error she received then was #Name? . I changed the examination of the zip code to be a separate field (txtZip) and now just concatenate the city, state, and pick up the txtZip. The error she now receives is #Error. Again, she is the only person out of 15 who get this error.

I did some testing to try to narrow down the problem. Bottom line - I imported the one production report with the problem into a small, temporary database using a link to the production table, and she can view the report just fine. But in my production database, she can not view the city/state/zip (she gets the error).

This user is able to see the city/state/zip on the report in my small, temporary database with every test that I've tried, but still can't see it in the production version. I tried to duplicate on this small, temporary database everything that I do during my installs (create MDE, password protect, encode, setup permissions) and everything WORKED in the small, temporary database but NOT in the production database.

Please HELP!!