I made a small change to the SMF Recent Topics module so that it checks to see if the user has the correct permissions to see the topic.  If the user does not have the correct permission then the topic is not displayed.  It is only a small change in the SQL that selects the topics to list.

I've tested the install, uninstall, and general use of it and everything is happy go lucky.   

The whole modules isn't working or just the change I made?

My guess is that it is due to PHP 5.  However I didn't write the module, just the small permissions change.  I would start a thread in this forum detailing your problem with the information you have provided in this thread, and include any error messages you are seeing on the screen or in any log.