None of my STools will work...

The problem is, if I try to load any saved games in Gmod, and take out any of my STools (even original default ones), then I get blue errors filling the corner of my screen, saying: “weapons\gmod_tool\shared.lua:150: attempt to call method ‘GetInfo’ (a nil value)”.
If I try either mouse button with the Tool out, I get another error where the method is ‘GetAimVector’ (I think).
However, if I start a new game up, I only get one different error and everything works fine.
So anyone have any idea whats gone wrong here?