what kind of internet connection do you have?

It's a broadband satellite connection. 

i'm guessing it's when the connection drops for a bit... how often does it happen?

We do get dropouts, but they are usually 20 seconds + and thus very obvious... I don't know if it could be dropping out for a nanosecond and causing that error, but I do know I haven't had the error on any other site, including using live chat etc...

 I would say I get the error maybe 10% of the time when I go to post a comment in the in-game chat box. 

k. noted. will investigate.

I've had the same problem....after that error, i also got this:

objErrorWindow is null

on line number 795

in file http://cdn-images.chesscomfiles.com/assets/js/qcodo_all.js

Hi,

I got the same kind of trouble when I wanted to create a conditional move: I had a sequence of 3 moves to record, so I played them in the conditional move stuff, when I played the last move I got this Ajax error (maybe not exactly "Ajax parsing error" but shtg with Ajax in it) and only the last move was recorded ! So when my opponen played the move I expected, the last move I recorded was played (instead of being played 3 moves later).

Sounds incredible doesnt it? I dont know if it is due to the same problem, and if anyone already got it... I opened a ticket for this