Create security pages not working

I've run the create security pages but none of the resultant pages seem to be working. When I first ran it, the wizard told me it didn't have rights to write the relevant table, so I had to copy the sql file it created and add it manually.

Anyway, now I've got login.php and registration.php (the only two pages I've been able to test so far). I have also got userupdate.php, forgotpassword.php and logout.php.

I click register from here http://brandchampion.co.uk/rental-furniture-detail.php?furniture=2 and have added a username and password, but they are not entering into the DB. Once I have submitted the registration page I am pushed back to the home page which has a URL ending in ?invalid=true. That's the first part of the problem.

The next part pertains to retrieving the user date from the DB. Because the registration didn't work, I entered the info manually. I then go to login.php and enter the details, but I get the same ?invalid=true. So log in is not working; that's part two of my problem.

Part three of my problem I guess is related to part two in that I am trying to retrieve the user ID via a session using the SecurityAssist_userID. If the session is not empty, then I will display certain content and hide register login buttons. If it is empty, then I display the register login buttons. I am certain that the session isn't being propulated because I have manually created a session like so $_SESSION['SecurityAssist_userID'] = 1 and have echoed it on the product page and it displays as expected. When I remove the manually populated session code and log in, the echoed '1' disappears.

Basically, I can't enter new user details, and if I manually populate the DB, I can't retrieve the detail to populate a session.

Any thoughts?

Server info in private message.

Thanks.