Apply Filter Error

[Tim B.]

I have a form with sevearl tabs, each tab contains a
subform (subform1 - subfrom10). I have a two combo boxes
(Box1 & Box2) on subform1. Box1 pulls info from a table,
Box2 pulls info from a query that has criteria from Box1
and from subform2. I have the docmd.requery "box2" as the
event procedure on After Update of Box1.

Problem:
After updating Box1 I receive this error message "You
can't use the ApplyFilter option on this Window."

Help Please, project due next week.

Thanks