Stops Calculating subform???

[Ryon]

Hello Again,
I have a invoice form with 2 subforms on it.one subform is for material and one for labor. I have a textbox(SUM) and(SUM) on each subform that totals the "totals" fields.

On my main form I have 2 UNBOUND textboxes that equal the subforms values. This is what I have as the control source for each Box.
LABORTOTAL =(CCur(FRMORDERDETAILS.Form!SUM))
MATLTOTAL = =(CCur([FRMMATLDESCRIPTION].Form!SUM))

After I get these values. I use VB to get these values to populate to bound text boxes.MATERIAL and LABOR. Here is the code I use for the form current event.
MATERIAL = MATLTOTAL
LABOR = LABORTOTAL.

everything works fine. BUT, after my suform(s) get more then 5 records in them, my calculations stop working. MATLTOTAL and LABORTOTAL on the mainform still have the values from the subform. It seems to not want to do the little = in VB.

Please help ASAP. I have around 5 people using this daily and this is becoming quite a problem. If there is a better way to get the values from a subform to populate to the bound boxes on the mainform, Please let me know. Thanks again,
Ryan