If this involves a site hosted by yourself you should try to change the memory_limit variable to say 16M and see if that works.
Otherwise you will have to ask your hosting provider to allow your scripts to allocate more memory.
Hope that helps.
EDIT: Why this out of memory issue occurs in your /modules/system/xoops_version.php file is a bit of a mystery though. Could be a weird coincidence but maybe you could post the contents of that file just to be sure?