It happen to me today so i decide to put the solution on my blog.
this problem happen because the script want more memory to process the specific task they do.
to solve this problem, you must change memory_limit = in php.ini file
if you can find php.ini file just do see it from using the phpinfo() function
<?php
phpinfo();
?>
i do recommend you set it up to 512M 😀
memory_limit = 512M