In the code window, go to:
Tools | Options | General
and set Error Trapping to:
Break on Unhandled Errors
While you are there, make sure the Compile On Demand is unchecked.
If that does not solve the problem, decompile the database. Make sure the
database is not open, and enter something like this at the command prompt.
It is all one line, and include the quotes:
"c:\Program Files\Microsoft office\office\msaccess.exe" /decompile
"c:\MyPath\MyDatabase.mdb"