Well I can't help you too :(
Apparently there are at least 900+ players are crashing, and crashing even more after the patch today which Valve stated it will fix client crash:
http://forums.steampowered.com/forums/showthread.php?t=2173339
One of the Valve employee in the Team Fortress 2 team replied in the thread that they will release a patch today, (Bellevue, Washington time [UTC -7], HK time [UTC +8], -15 hours total) which means the patch will be out around tomorrow 8:00 or 9:00AM in Hong Kong. I will update the server on around 11:00AM tomorrow plus some maintenance operations on our side.