WPMU causes issues with the theme i'm using

Hi there, since i installed WPMU and smushpro (i was using the free version before) I am having issues with my theme http://themeforest.net/item/the7-responsive-multipurpose-wordpress-theme/5556590 (The 7.2)

Your dashboard and the upgrade from free to paid smushpro are the only changes i have made so i'm pretty sure that's where the issue is.

What do you recommend I do in this situation?

Thanks