This is just a band-aid until someone actually goes ahead and ports this to a later version of .NET because I can't imagine this will be backwards compatible forever. I've only tested exporting item's icons, but I imagine not all functionality works in .NET 4.0 without porting the code over. If this doesn't work for you, install .NET 2.0, I guess.
I had to just make the following change to get POLUtils to run in .NET4.0 (instead of installing .NET 2.0, yuck):
This is just a band-aid until someone actually goes ahead and ports this to a later version of .NET because I can't imagine this will be backwards compatible forever. I've only tested exporting item's icons, but I imagine not all functionality works in .NET 4.0 without porting the code over. If this doesn't work for you, install .NET 2.0, I guess.