It means that "sc-main" is empty table or nil. You must check it before.
Well, if you are not the author of the mod, then you can complain about that in the mod's thread, if it has one or at the discusson section of the mod portal. This one error is caused by some "selectcharacter" mod.

If you ...

Kailio wrote:

darkfrei wrote:Can you show this part of code? Control.lua, string 48.

With notepad++ it's simple.

How might I find it? If I knew how to find it I can easily show it with notepad++

Never mind, I have it and if I am not mistaken this is what it says

darkfrei wrote:Can you show this part of code? Control.lua, string 48.

With notepad++ it's simple.

How might I find it? If I knew how to find it I can easily show it with notepad++

I'm not sure if this is the right place to put this, but I believe it is.
I recently started using mods, recently as in today but throughout today I've noticed these errors I've been getting while in game after doing / pressing certain things. As the picture shows it will come up with this notice ...