I've mounted an underbarrel shotgun, but when I try to reload it (since it starts empty) it gives me this error.

File exists in two addons - possible conflicts! lua/weapons/arccw_base/sh_ubgl.lua (ArcCW and ArcCW CS+)

[ERROR] lua/arccw/shared/attachments/ubgl_mass.lua:78: attempt to compare nil with number
1. reloadfunc - lua/arccw/shared/attachments/ubgl_mass.lua:78
2. ReloadUBGL - lua/weapons/arccw_base/sh_ubgl.lua:108
3. unknown - lua/weapons/arccw_base/sh_reload.lua:13