Cart66 lite plugin disables admin login and dashboard

I haven’t changed anything on my site for the past few days, and today all of a sudden I can’t login to my dashboard. If I go to my wp-admin page the whole thing is blank. The site itself works fine, but I can’t access my dashboard at all.

I started deleting plugins to figure out what was causing it, and it’s the Cart66 lite plugin. If I delete it everything works fine, but I can’t delete this since my entire e-commerce is set up around this plugin. I know Cart66 doesn’t offer support for their free plugin, but I certainly don’t want to pay to upgrade and possibly still have the same problem. If anyone has a solution for me I would appreciate it!

http://wordpress.org/extend/plugins/cart66-lite/