Formatted Search on form designed using Screen Painter

Hi,

I have a form with several text boxes and would like the formatted searches assigned to them, to work dynamically, based on the contents of the preceding text box.

My form is 2000060017 and the item is ITM2. Can somebody explain why the following syntax is incorrect/not working?

SELECT U_Bin, U_OnHand FROM [@BLOITW] WHERE U_ItemCode = $[2000060017.ITM2]

Also, is there any issue with using the selected value from a combo (ITM17) on this same form?

Thanks for any help,

Robin