[Silvers]

Viewing raw the last thing mentioned is "l4d_Chat.smx" and "Removing Overide for Client Louis" while in yellow at the top it says "IVP Failed at /home/buildbot/buildslave/l4d_rel_linux/build/src/ivp/ivp_physics/../ivp_utility/ivu_vhash.cxx 157"

Could try removing that plugin. If that doesn't fix it then I would recommend removing half of all plugins and testing, continue removing/restoring half until you find the culprit.