PGENGA04, I also recently upsized my mdb to an adp. Since the queries that you are viewing in the adp are actually sql objects, using Forms!MyForm!MyCotrol will not work since sql does not recognize this format. You will instead have to declare a variable to recieve the value of MyControl, and then have your front end pass this value whenever it calls your "query".
Also, I am finding that I like editing my "queries" through SQL Query Analyser much more than through the adp file. You may want to study how it works, along with the Enterprise Manager as they are both turning out to be extremely handy.