Hi,
It seems memory limit issue. Methods for increasing the amount of memory a PHP script may consume
1. If you have access to your install and are running a version of WordPress earlier than 3.0, try the plugin
http://wordpress.org/extend/plugins/memory-bump/ as this is the easiest way to increase your RAM for WordPress. [Mod note – Link Added 2010-06-21]
2. If you have access to your PHP.ini file, change the line in PHP.ini
If your line shows 32M try 64M. If your line shows 64M try 128M
memory_limit = 64M ; Maximum amount of memory a script may consume (32MB)
3. If you don’t have access to PHP.ini try adding this to an .htaccess file:
php_value memory_limit 64M
4. Try adding this line to your wp-config.php file:
Increasing memory allocated to PHP
define(‘WP_MEMORY_LIMIT’, ’64M’);
5. Talk to your host.
Thanks
Mohammad
.