I have a Livecycle designer 8 form and used dynamic dropdownlist with ODBC connection. After applying usage rights to the form using acrobat professional when i open with reader my first dropdown is showing records but the dependent dropdown in blank. If i open the same form with acrobat it is working (The second dropdown is populating records according to first dropdown).
Let me just rephrase what PDFGuru said: You cannot do that by adding extended Reader rights in Adobe Acrobat Pro, you need LiveCycle server software for that. It's a common misconception that there is just one set or extended Reader rights and that one can assign all of them with Acrobat Pro.