I have a simple html for that collects a userid and a password.  I then verify
the user id/password using a seperate php script.  In the php script I query
a mysql database and search for a userid with a matching password.   The very first line in my script checks to make sure the userid and password variables are set (before even touching the database).  If not I output an
error and kill the script.  If they are set but incorrect (after checking against the database) I generate an error and log it into the db.  The problem is if the userid and password are CORRECT, the variables are unset, like the post from the first html page never happened!! If I use an invalid userid and/or password then the variables remain intact and the script executes as expected (logging an error end exiting).   I have never seen anything like it before.  If I can provide more elaboration, please let me know.

Matthew