for the redirect to previous url option to work, the forms action on the login page must pass any querystring variables that are passed in on page load.
set the login forms action to use the following code:
<?php echo htmlentities($_SERVER["PHP_SELF"]); ?><?php echo (isset($_SERVER["QUERY_STRING"]) && $_SERVER["QUERY_STRING"] != "")?"?".htmlentities($_SERVER["QUERY_STRING"]):""; ?>
we are short handed in the support department this week due to an emergency, we will get to your ticket ASAP.