Sassilization Lua Error's?

ERROR: GAMEMODE:‘ShouldCollide’ Failed: STBase\gamemode\shared.lua:41: attempt to call method ‘IsGhost’ (a nil value)
entities/st_hat/cl_init.lua:18: attempt to call global ‘STValidEntity’ (a nil value)
entities/st_hat/cl_init.lua:18: attempt to call global ‘STValidEntity’ (a nil value)
entities/st_hat/cl_init.lua:18: attempt to call global ‘STValidEntity’ (a nil value)
entities/st_hat/cl_init.lua:18: attempt to call global ‘STValidEntity’ (a nil value)
entities/st_hat/cl_init.lua:18: attempt to call global ‘STValidEntity’ (a nil value)
entities/st_hat/cl_init.lua:18: attempt to call global ‘STValidEntity’ (a nil value)
entities/st_hat/cl_init.lua:18: attempt to call global ‘STValidEntity’ (a nil value)
entities/st_hat/cl_init.lua:18: attempt to call global ‘STValidEntity’ (a nil value)
entities/st_hat/cl_init.lua:18: attempt to call global ‘STValidEntity’ (a nil value)
entities/st_hat/cl_init.lua:18: attempt to call global ‘STValidEntity’ (a nil value)
entities/st_hat/cl_init.lua:18: attempt to call global ‘STValidEntity’ (a nil value)
entities/st_hat/cl_init.lua:18: attempt to call global ‘STValidEntity’ (a nil value)
entities/st_hat/cl_init.lua:18: attempt to call global ‘STValidEntity’ (a nil value)
ERROR: GAMEMODE:‘ShouldCollide’ Failed: STBase\gamemode\shared.lua:41: attempt to call method ‘IsGhost’ (a nil value)
ERROR: GAMEMODE:‘ShouldCollide’ Failed: STBase\gamemode\shared.lua:41: attempt to call method ‘IsGhost’ (a nil value)
ERROR: GAMEMODE:‘ShouldCollide’ Failed: STBase\gamemode\shared.lua:41: attempt to call method ‘IsGhost’ (a nil value)
ERROR: GAMEMODE:‘ShouldCollide’ Failed: STBase\gamemode\shared.lua:41: attempt to call method ‘IsGhost’ (a nil value)
ERROR: GAMEMODE:‘ShouldCollide’ Failed: STBase\gamemode\shared.lua:41: attempt to call method ‘IsGhost’ (a nil value)
STDeathrun\gamemode\shared/meta.lua:9: attempt to call global ‘STValidEntity’ (a nil value)
STDeathrun\gamemode\shared/meta.lua:9: attempt to call global ‘STValidEntity’ (a nil value)

Help?