See the on-line handbookhttp://support.epson-europe.com/onlineguides/en/sc84/index.htm
and look in Problem Solver, Diagnosing the Problem, Error indicators. If the two lights are flashing together, you have a paper jam. If this is the case, you should be able to pull the paper out from the front or top. If the lights are flashing together, and you can't see any paper jamming the printer, post a new comment to this effect for more help.
If the lights are flashing alternately (Unknown printer error),
it usually means the Waste Ink Pads in your printer are saturated with ink and the waste ink "protection" counter has exceeded its limit. You can restore your printer to a working condition immediately by using the SSC utility - download fromhttp://www.ssclg.com/epsone.shtml
and use it to reset the Protection Counter. This will stop the lights flashing and restore normal operation. However, remember that eventually ink will overflow from the waste ink area and make a dreadful mess, so you should change the waste ink pads before this happens. This requires the disassembly of the printer.
If you decide to have a go at replacing the ink pads yourself, report back with a new comment and I will provide further help.