Activity Feed, Groups, Members = Blank Pages

Hi,

I have a big problem with my website 1freechat.com as suddenly items are not appearing on the wall, activity feed, members lists of groups pages. Sometimes also the top menu will not extend, drop downs sometimes do not work to reveal the menu items.

I have not added any plugins to when the site last worked or done anything to edit the site, it simply has stopped working. I also disabled all plugins and still have the same errors. I have also reverted back to a default theme and the errors are fixed, so the problem seems to be the theme somewhere, however, I cannot fix it so I am asking you to please take a look.

As you can see here http://1freechat.com/members/ members are not showing and the menu is not revealing.

As you can see here the activity feed is blank but the menus are working http://1freechat.com/activity/

Please help asap.

Thank you

Simon.