Actually I've seen this problem posted numerous times, over the years, and the usual culprit is a Timer Event that is running, either in the Form in question...or another Form, if open at the same time. I'm guessing it's in the same Form, in this case, or in the exterior database that you're referencing, and when you remove the reference to the library/db, you're halting all code from firing.
The trick is to find out where the Timer is running and disable it while you're developing your db.
Linq ;0)>
The problem with making anything foolproof...is that fools are so darn ingenious!
All posts/responses based on Access 2003/2007