runtime error when running from player

OK so my game crashes when I run it from the player but not from the editor. It crashes specifically when I instantiate a skinned Mesh.

If I delete the .exe and the data folder and rebuild, it crashes. However if I delete the same things, run the game in the editor, then build, then run the player, the game does not crash but the script running on the created instance is not working properly, almost as if it were an older version of it. Any suggestions?

I have tried reimporting all assets.

Here is the stack trace from the crashlog:

 ========== OUTPUTING STACK TRACE ==================
 
 (0x004ABA65) (Zombie Harvest): (filename not available): AnimationEvent::Transfer + 0x14645
 (0x004ADF17) (Zombie Harvest): (filename not available): AnimationEvent::Transfer + 0x16af7
 (0x004AE20B) (Zombie Harvest): (filename not available): AnimationEvent::Transfer + 0x16deb
 (0x003F640B) (Zombie Harvest): (filename not available): Behaviour::Transfer > + 0xe9aab
 (0x003F6A4D) (Zombie Harvest): (filename not available): Behaviour::Transfer > + 0xea0ed
 (0x75F5336A) (kernel32): (filename not available): BaseThreadInitThunk + 0x12
 (0x77C19F72) (ntdll): (filename not available): RtlInitializeExceptionChain + 0x63
 (0x77C19F45) (ntdll): (filename not available): RtlInitializeExceptionChain + 0x36