Exceeding Allowed Memory Size
 

I'm exceeding the allowed memory size on my forum, and recently received an error:

Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 544241004 bytes) in /home/*******/public_html/includes/init.php on line 45

I don't think the forum is very big at this time. While I know that modifications are not officially supported, is it possible that is causing an issue, or is this not abnormal for vBulletin?

The forum has a DB of about 100 MB, 60K posts.