It's a new install, and I'm a teensy bit past noob with Linux systems, but I've used Mint before, and Plex works fine on my WIn7 OS. Plus, it worked fine for a few days on Mint... When I log into Plex Media Manager online, the libraries and shows are still there for my Mint server.
I've relinked my Roku to Plex via the 4-character keycode, and deleted all previous servers. [EDIT] When I try to discover servers automatically from my Roku, Windows7 will show up, but it can't find anything when my computer is running Mint. Manually adding a server at 192.168.1.2 / 32400 (checked that IP via ifconfig) times out without making contact.