If you get an error, but you have no idea what is happening, you could try to narrow it down in the code, if you feel comfortable with PHP. Then, after you found the offending line, you should insert the line
print (mysql_error());
immediately after it. This will give a more descriptive message of the error and hopefully lead you to a solution. We already used this trick in Section 3.9.2. See also Warning: mysql fetch row: supplied argument is not a valid MySQL result resource and submit news problem.
PHP-Nuke HOWTO in module form by Chris Karakas
