332899 Email Script Database Issue

We purchased an email script from a company that does not support their work once they get paid so what we have is a completed script that has one issue that we are having difficulty with. When you sign up for an account it logs you in immediately but once you log out you cannot login. We checked the database in phpmyAdmin and found that the information for the new user did not write to the database. We think this may be a php4 to php5 issue but are not certain. We need someone that can browse through the script and remedy this bug. There may be additional issues in the future as we have not fully tested everything and would like to keep chain of communication open with the programmer we hire. Thanks