To debug this please open your Products_Results page under Admin, and put this line of code at the top of the page:
<?php die("redirect"); ?>
And try logging in again and post back with your results.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.