I have re-compiled the source axis sniper model to use a custom skin server side so all players can see it for my Zombie Mod but I get this error in the console

Performance warning: Mark bone 'ValveBiped.weapon_bone' in model 'player\SAS_ZombieMod\zombie\german_sniper.mdl' as being used by bone merge in the .qc!


...also, although I'm not sure its related, the server crashes randomly while running the mod with this error.

Bad entity in IndexOfEdict() index -37116284 pEdict 00000259 sv.edicts 2C3F0010

The models themselves work fine but I really need to get to the bottom of the crashing.

Are the two errors related and how can they be solved?