Comparing Date (1 Viewer)

Hi, i want to create a subform displaying all staff in my database that over due for their next training session, there should be one each year, its on frmOverDue, my staff lift is Staff List and im comparing it to the date (mm/dd/yyyy) of their last training 2012 within that table.
i have a =date() text box on my form im using so i use that to compare, i tried this in the 2012 criteria section of the query but it didnt work:
iif ( Forms![frmOverDue]![txtDate] - [Staff List]![2012] > 11)
I havent access for ages and im doing a friend a really urgent favor but i keep tripping over simple little errors :banghead:

You might want to look into the DateDiff() function.