Lua Error fix?

[leiaparx]

Is there a way to fix this? I have not seen this pop up before.

Message: Interface\AddOns\SubSpec\SubSpec.lua:131: attempt to index field '?' (a nil value)
Time: 03/18/18 14:00:15
Count: 1
Stack: Interface\AddOns\SubSpec\SubSpec.lua:131: attempt to index field '?' (a nil value)
[C]: ?
Interface\AddOns\SubSpec\SubSpec.lua:131: in function <Interface\AddOns\SubSpec\SubSpec.lua:126>

Locals: