ApplyFilter Error 2501

[torok]

I'm getting an error I can't figure out.

My form allows me to apply a filter once (via code), but if I try to do it again when a combo box value changes it complains with an error, saying "The ApplyFilter action was canceled"

Anybody encountered this error before?

 

[torok]

OK, apparently it happens when after I apply the filter I get no results - but Access thinks I'm making a new record and complains about how it can't resolve the foreign keys. This is really annoying.