Runtime 6 - Overflow ?

[JohnY]

I was working on my inventory and when I try to login to my game
I get Runtime 6, Overflow, it highlights this:



Does anyone know what causes overflow?
I tried to figure out the answer, but couldn't find anything usefull.

EDIT: I tried making a new character and login.
Now I get runtime 9 - Subscript out of range.