How do you enable this with helix?

Hello, my friend get this lua error, u know what that mean ? (Owner of the server say "it comes from him") but, idont undertsand how :E
(of course he uninstalled everything and reinstalled + uninstalled / Deleted the .gma in the files and reinstalled everything = still the problem)

"[the_perfect_training_system] addons/the_perfect_training_system/lua/diablos_training/vgui/cl_dumbbell.lua:187: bad argument #1 to 'WriteUInt' (number expected, got nil)

1.WriteUInt - [C]:-1
2.DoClick - addons/the_perfect_training_system/lua/diablos_training/vgui/cl_dumbbell.lua:187
3.unknown - lua/vgui/dlabel.lua:237"

Ty to help