Sounds like a module is causing a conflict with something else on your computer, try downloading a different theme or commenting out modules until it loads properly. I would even comment out every module except the one that runs the popup menu then turn them back on one by one until it freezes again. Just recycle Litestep each time until you find the module that is causing problems.

If it freezes even with all the modules commented out then it's obviously another problem, but at least you've narrowed it down some ;)