Form fails after adding a lookup field in a split DB

[bener]

I have a split database. I added to an existing backend table ("Table-A") a new lookup field ("Field-1"), based on another (new) backend table. I added a link to the new table on the frontend. The moment I add Field-1 to the RecordSource query of an existing form based on Table-1 and try to update something on the form, I get the following error message: "The expression After Update you entered as the event property setting produced the following error: Member already exists in an object module from which this object module derives."
I would like to mention that Table-A has other similar lookup fields which existed prior to the DB split, and they work perfectly.
Any solution or workaround would be much appreciated.

[bener]

I have a split database. I added to an existing backend table ("Table-A") a new lookup field ("Field-1"), based on another (new) backend table. I added a link to the new table on the frontend. The moment I add Field-1 to the RecordSource query of an existing form based on Table-1 and try to update something on the form, I get the following error message: "The expression After Update you entered as the event property setting produced the following error: Member already exists in an object module from which this object module derives."
I would like to mention that Table-A has other similar lookup fields which existed prior to the DB split, and they work perfectly.
Any solution or workaround would be much appreciated.

After further investigation, it probably has nothing to do with the split DB. I undid the split and defined everything from scratch, the problem still occurs!

[RuralGuy]

Have you read this link yet? http://access.mvps.org/access/lookupfields.htm