Before going to the last resort (see below), have you tried connecting the printer directly into the computer's USB port, bypassing the the router? That will at least let you know if the problem is in the router or not. Also, have you powered down everything, and then repowered them back on? That is the easiest, least intrusive, thing to try. It will sometimes fix things - without endangering anything.
I had an 3800 issue too, and while not at all the same situation other than the 3800, I fixed it. I had updated the driver, and then lost all contact between the printer and computer.
I'm connected the 3800 by ethernet via an Airport Extreme, and I'm still at 10.5.6 - so as I said, not quite the same situation.... but perhaps this will suggest a solution.
I had to "reset" the printer system and then reinstall the Epson printer drivers, as if I were starting from new again. You also have to reinstall the other printer on the system, but at least in my case that just happened automatically as if I were adding the printer for the first time. OS X had drivers for it built in.
To reset the printer subsystem, go to Preferences > Print & Fax. Then right click (or ctrl-click) on the printer icon in the sidebar. In my case it reset the printer subsystem for both my printers.
This may be a last resort solution.
Good Luck.