On a copy of the DB, go back to the original form that is causing trouble. Starting at the header, check each sub routine and function. Make sure each one has a start and finish, a Sub and end sub.
If all looks well, Make a copy of the form, only this time don't copy the entire VBA. Paste each routine over, one routine at a time. All the while make sure that you create a new routine or function to paste into, A new start and finish.
You can do this by copying the first line without the parenthesis and then hit the ENTER key. Then copy the routine and paste inside.
Example:
Paste
Private Sub Command1_Click
then hit enter to get
Private Sub Command1_Click ()
End Sub
This will give you something to paste into.