I took a quick peek at your website and couldn’t immediately see what was going on. But, what I do in those kinds of situations is to try and pin down where the error is. You can try opening your CSS file and take out the bottom half of the file (save a backup obviously =D ) and refresh. If that fixes the problem, you know the problem is in the half you removed.
From there, rinse and repeat this process of taking out chunks of your CSS until you find the rule/rules that are causing the error. Hope that helps you get it figured out!