I'm guessing that your issue is that you get a parameter prompt? That would have been so much more helpful.
Look at the spelling of the form in the query and compare that to the spelling of the form.
Now you have another reason to not use long convoluted object names. Fixing that will get rid of the parameter prompt but there is more to do since the 2nd combo produces no results. Getting late here now so I will refrain from digging deeper for tonight. You have table design issues beyond names. In a related/child table you don't store the primary key as a foreign key AND the value that the key represents. In other words, if 2 means video, in the child table you store 2, not 2 and "video".
EDIT -forgot to mention that the same error keeps popping up - something about requerying a query in form events. Why do that?
And I guess I'm too curious. The empty combo is because you have 2 fields in the underlying query yet you have 3 columns in the combo. Cut the count to 2 and remove the last dimension value for column width.
You have to understand that binding combos means that if you play around with values you can change the record field value by accidentally changing the combo selection. So beware.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.