Thanks for the update.
I established late last night that the problem, as you state, has nothing to do with register_globals so in that respect I am happy as I know now that going forward SecurityAssist is not an issue with regards to this :)
The problem is, with the help of the script you supplied, a session management issue.
It appears that i do not have the appropriate permissions on my folder to enable writing of the session (to, I assume, the default session_save_path).
Is it therefore possible, within the folder, by use of a php.ini file or similar to set the session_save_path to this same working folder?