We ended up replacing a 3 year old Toshiba for this reason and will never go back.
If this is the case, what happens if you take the server out of the picture (ie just create a TCP/IP port on the x64 Windows 7 machine so it treats it as a local printer) - do this with the Windows own driver (rather than downloading the Epson driver). If that doesn't work them I'm stuck but if it does work then maybe there's something wrong in the way the driver's configured on the server (but I must admit I'm not sure what to look at)
I just find it weird that a driver which is supplied with Windows won't actually print anything!
I have an x64 Server 2008 with drivers for the printer. We tried all sorts of drivers even the generic Epson driver. The server cannot print although it appears to; just nothing comes out the printer. Both 32-bit XP and 32-bit Win 7 cannot print via the server.
Our old 32-bit Server 2003 works fine and local 32-bit machines can print directly to the printer or via the 32-bit server. We don’t have any 64-bit machines to test with.
When I get a bit of time in a few weeks it will be worth trying your idea of a local 64-bit machine printing directly via TCP/IP.