I'm guessing in the config (a munged odf is an example of a config) file for this "pebble" or whatever there was supposed to be a data chunk but it was mysteriously not there. Could indicate a munge error. I'm not sure if pebble is a clever name pandemic made up, or if it indicates some new type of class.
The best way to track down this culprit is to undo whatever changes or additons you made to your map before you started getting this error, then munge and test each time you add something back until the error creeps up again.
I know this is an old topic, but I feel that the bump is warranted. I got this error a couple days ago working on the Pack, and it scared the heck out of me, because it caused nearly every map to crash. (And no one knew how to fix it or debug it, or so looking through old topics led me to believe.)
I ended up fixing it, and with some whittling-down of possible causes I finally figured out that one of my .hud files in a custom side had a misspelling "MesshInfo" instead of "MeshInfo."
I can't say for certain that this error is only caused by an issue in a custom .hud file, but I can tell you that that my problem (which resulted in the same error) was caused by a custom .hud file issue. Hopefully this'll help someone in the future.