So do I understand that you have the HP Color LaserJet 8500 PS installed and it is working well, but that you cannot get the HP Color Laserwriter 4600dn to install and work?
Is either of these connected directly to your Mac? Or are they both on the LAN?
If they are on the LAN there are multiple issues to address. I'm really straining my memory to remember what issues I had when having problems with multiple OS's on my LAN. Someone might correct me on this, but it seems, for example, when Vista tells me I can't print to a printer attached to an XP machine on the LAN, that the problem is in the driver installed on the machine hosting the printer, not on the machine that you created the document on.
Secondly, in dealing with a LAN trying to integrate a PC with Macs, there are multiple issues involved. You can read about it more here and possibly find some solutions:
http://tinyurl.com/ybgaxeqYou might find it easier to configure Parallels to share a folder on the Mac partition, save your work there, and then print it with the Mac application. Alternatively, use a "tennis shoe net" by saving your file to a thumb drive and take it to the print server.