In this case we need to increase PHP Memory limit. These are the different ways to increase it:
1) Please check php.ini file in the root/public_html folder of your site. Open php.ini file in text editor and change the values for memory_limit. By default it should see memory_limit = 8M. Try changing it to 12M. if it wil not resolve the problem then try to increase it either 16M or 24M.
2) If you can’t find the php.ini file, open up the PHP file which requires more memory and add this line just after ini_set(’memory_limit’, ‘12M’); we can increase memory upto 16M or 24M to resolve the issue. But do it try with 12M first.
3) In last, open the .htaccess file from the root/public_html folder and add this line php_value memory_limit 12M
From anyone of these trick you can work and rid out from the PHP error.