Thanks. I suspected it might be the PHP 4, since I get an error on another component indicating a conflict with that version of PHP.

I will recommend that the site owner buy the paid version of your component, assuming everything is working when the PHP upgrade is in place.

Fatal error: Call to undefined function: array_diff_key() in /hsphere/local/home/irides/intermarkridegroup.com/components/com_sef/joomsef.php on line 703

It's actually not a 404. Joomla version is 1.5.15. JoomSEF version is 3.5.5. Site is intermarkridegroup.com.

As I mentioned, I just took over the site. There are modifications made by a previous admin to discourage hackers, so I'm seeing a few configuration oddities that are unfamiliar.

I just took over an existing site with JoomSEF installed. We noticed a problem today after I updated from the older version. The site home page comes up fine when the URL is entered. Click any menu item, and the "Fatal Error, Call to Undefined Function" error appears. Return to the previous page, and now everything works fine. All links function, including the one that was broken a moment before.

I will continue trying to find a solution in the documentation, but any help would be greatly appreciated.