I checked the issue both on Forumotion.com and the AvacWeb website, the issue was with an update Forumotion.com recently added. As Explianed by LGforum, and i quote:
LGForum wrote: The bug was caused by something FM is doing to the data cookie which stores session data and more. It looks like they're going to include the users last post within that cookie.
This means we'll be able to access the last post data, from anywhere
EDIT: Clear your browser's Cookies and Cached data and it should be fixed. This is a temporary fix and it'll NOT work for everyone, but for the majority, it should work.
EDIT #2: Just FYI, the issue hasn't still been fixed, you can keep an eye on this topic if you want: http://www.avacweb.com/t2014p15-avacweb-chat-problem
I'll let you guys know when they fix it.