Enable flags 16 and 32 in g_classWeapons http://mygamingtalk.com/wiki/index.php/Silent_Mod_Server_Cvar#g_classWeapons to go around the bug. Ensure that these flags are set with rcon. The reason why this happens is that when the player clicks the team button in the limbo panel, the default class is soldier and if the bottom weapon in the expanding weapon box is not available for selecting, this error will close the client. Note that it happens exactly when clicking the team button.