I know this is an old thread but this thread came up on a search for "System.IO.IOException" error while connecting to my printer. If you installed the driver from Matter Hackers, you need to open Device Manager and find the entry for your printer. Mine was under Ports>COM4(yours will be a different number). Right click your COM Port and click Update Driver. Then select Search Windows Update. It will update the driver and you should be able to connect.
Posts made by RossRobotics