Yes, uninstall the Windows Printer. If you are using OPOS, you do not want the printer to be listed as a Windows printer. Also, check for any other Windows devices that are using the same PORT as your printer, even if they are not physically connected to the computer - for instance, Quickbooks installs a driver for a print to file option and assigns it to LPT1 by default. If you have an OPOS parallel printer on LPT1 and there is one of these ghost printers assigned to LPT1, you will get OPOS errors. There are other programs that install similar objects - Quickbooks was just the first one off the top of my head.
Other than that, make sure you have selected the right printer model and interface and if you are still having problems, check the firmware version of your printer - there are instructions on the EpsonExpert site.