I've experienced this before, so I had to do a lot of research to fix it. That's what it was the last time I dealt with it, but we're still not sure yet.
If you can you should submit this to woocommerce tech suppport or forum as well, since somebody there may have already solved it or they have a patch for it.
I'll look into it and see if I can write you some simple steps. In the meantime it wouldn't hurt to get familiar with your php.ini file.
www.ostraining.com/blog/coding/phpini-file/ This is a joomla article but it explains how to make changes to a php.ini file.
www.ostraining.com/blog/joomla/installation-problems/ And here's how to solve the most common problem with WordPress and php.ini
www.ostraining.com/blog/wordpress/wordpr...allowed-memory-size/ Anyway, let me see what I can suggest specifically.
Ed