Hello
I got the same error message and i managed to fix it.
Right-click on plutonium.exe → Properties
Go to the Compatibility tab
Check: Run this program in compatibility mode for: Select Windows 8 from the list
it fixed it for me.
Hope it can help some people
mp_outskirts is Stockpile, a DLC map. Do you have the DLCs installed? Because if you don’t, then you need to do so to play DLC maps as Plutonium doesn’t provide game files.