For a while I've had intermittent trouble with the chat and the bip system, for a while it worked perfectly, then it stopped working entirely on firefox and the bip didn't work on IE. After the site update this worked perfectly again for a brief time then went back to only working on IE.
I tried to get into the chat earlier tonight and found that it didn't want to work, in firefox, IE, or dragon. so I got kind of cheesed of at it and, after a bunch of toggling addons etc. on and off, went back to firefox and fired up firebug. Eventually I found that I was getting a '404 not found' error at
both when the page loaded and then when the next message came in (the second attempt seemed to e the one that was crashing the chat for me). So I went into chat again and didn't turn the bip on (in retrospect, something I should have done sooner), and it didn't crash.
Given this, I changed my bip setting and now everything works fine. As far as I can tell the bip setting in my profile got lost and when the firefox tried to find a file that doesn't exist the chat crashed, resetting the call fixed the problem. Interestingly IE used to just suppress the error.
Unfortunately I don't know enough about how the site is setup to tell whether this was my profile getting messed up or just my cookies getting messed up (another thing I should have checked tonight, I think I purged cookies in a previous attempt at solving this problem).
So, tl;dr version:
So if the chat keeps crashing or the bip doesn't work, reset your biptype in user CP -> profile, that fixed it for me.
I hope that this helps anyone else that's been having trouble with the chat/bip.