I went to print from Windows running under Parallels on my Mac and it didn't work, although it had in the past. I tried the usual highly intelligent :-) problem solving technique of rebooting (in this case both Windows and the Mac) but it didn't help.
Eventually I remembered that I had switched the printer from USB to Firewire, since the printer (Epson R1800) had come with a Firewire cable and it freed up a USB port.
But ... Parallels doesn't virtualize Firewire, only USB. There are several workarounds but none of them are great since they don't let me use the specific features of the printer.
Now something else made sense. I had wondered why I had an HP postscript printer set up in Windows. I hadn't set it up myself so I assumed some application I had installed had done it, although that didn't make much sense. Now I realize Parallels must have created it as a way to print to Mac printers.
Another workaround is to print to PDF on Windows and then print the PDF from OS X - a bit tedious, but it works.
I may end up moving the printer back to USB, but that'll mean messing with the setup on OS X which I'd rather not have to do.
The reason I wanted to print from Windows was because I was using Canvas, a program that combines many of the capabilities of Photoshop and Illustrator (i.e. both vector and bitmap at the same time). I really like Canvas but it's been somewhat abandoned. The product was bought by ACD who haven't done much with it. There was/is a Mac version but not for Intel, so I'm still using the Windows version. There are rumors of a new Windows version but not Mac. Too bad.