UBB.threads PHP Forum Software Community Forums UBB.threads 7 Version 7 Support PHP Fatal error: memory limit

Recently moved to a new host, running ubb.threads 7.5.6 along with MySQL/PHP 5. In my apache error_log I'm noticing a lot of the following messages:

[Mon Jun 04 23:48:12 2012] [error] [client X.X.X.X] PHP Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 523800 bytes) in /my/path/to/ubbthreads/libs/html.inc.php on line 119

According to php.ini, my memory_limit is at 64MB.

What could be causing these errors, and, how do I resolve them?

Thanks.