Hey guys, I’ve had the same issue and found on the wp-ecommerce forums it can be solved by increasing the php memory.
Put this in your wp-config.php file: (‘WP_MEMORY_LIMIT’, ‘128M’);
I use this on majority of my wp sites at the bottom of wp-config.php and it usually works. Makes your site pretty fast too. 64M is what I normally use but on the wp-ecommerce forums they say to use 128M.
If that doesn’t work, here is a great resource on how to increase your php memory:
5 Ways to Increase the PHP Memory Limit in WordPress
I hope this helps.
