If you can spare the memory, up your max memory in the php.ini to 96m or 128m. Ensure that you leave enough memory for current server processes to continue to serve pages. If you're running Apache, that will require you to take a look at a typical process memory usage (which is easily accomplished with
ps or any of the myriad of tools.
Multiply the amount of memory each process seems to use, and then scale the server by manipulating the data in the server (I'll assume Apache) configuration. Apache has a great page on scaling to tune performance here.
Combined, you'll likely find that those will keep your server alive long enough to diagnose the problem as a configuration or a PHP script problem, at which point you'll have to ask a more direct question.