This error relates to the limited PHP memory size. Below is my suggestion:
– If you have access to your PHP.ini file, change the line in PHP.ini. If your line shows 32M try 64M: memory_limit = 64M ; Maximum amount of memory a script may consume (64MB). Here we consider 64M as good configuration. Depending on your need, server codition, how is your site, you could use 32M, 96M, 128M, 256M, 512M, 1024M, 2048M, 4096M. Make sure your server allows you to use that much dedicated memory.
– If you don’t have access to PHP.ini, please try to add this to a .htaccess file: php_value memory_limit 64M
This relates to server side so it would be best if you talk to your hosting provider to get help on this.