DarqUI targets .NET 4.0 and it updates EQ2MAP just fine if you're still having trouble.
You can use the DarqUI utility to install only
EQ2MAP without DarqUI. Answer No No Yes Yes
to the four options when you install, and the utility will take it from there. You can come back to the EQ2MAP utility page to update your maps any time. Please post again here if it gives you any trouble.