Silly question but, have you printed from this printer before?
If you haven't, try to see if it is listed in under your computer's "Printers and Faxes" If it isn't, you may need to give the driver installation another go.
I do not know the full extent of how you put the printer in, but you need to install a driver, many times, it just comes inside the printer and installs when you plug it in, but sometimes, it comes on a disc or you need to find it on the internet.
Pepakura Designer has a crap load of different printing configurations when you get the printer to work, but mess around with those too after this problem is fixed.
Good luck to you!