Hi Jeff.
>> ThisForm.ItemNumber.ROWSOURCE = CORR_REG.QUEST_NUM
ThisForm.ItemNumber.ROWSOURCETYPE = 6
ThisForm.ItemNumber.CONTROLSOURCE = CORR_REG.QUEST_NUM <<
A couple of things here. Nancy pointed out that you need quotes around the RowSource. You also need them around the ControlSource. But you have a problem here that is a different issue. You do not want the controlSource and the RowSource for your combo to come from the same table. This will cause you all kinds of problems. Generally speaking, combos pull their values from one table (usually of lookup table) and use the selection to populate a different table with the selected value. The can also be used for navigational purposes.
To reset your RowSource, you may also want to try something like this:
WITH Thisform.ItemNumber
.RowSource = ' '
.RowSource = 'Corr_Reg.Quest_Num'
.Requery()
ENDWITH
Marcia