Magazine error

Error in hook PlayerBindPress: addons/spieslikeus/lua/weapons/swep_magazine.lua:117: Tried to use a NULL entity!
stack traceback:
    [C]: in function 'GetClass'
    addons/spieslikeus/lua/weapons/swep_magazine.lua:117: in function 'fn'
    addons/ulib/lua/ulib/shared/hook.lua:179: in function <addons/ulib/lua/ulib/shared/hook.lua:162>
    [C]: in function '‌‎​‬‪‭'

[ERROR]
  1. unknown - [C]:-1