I googled CD printing, found and copied this fix for future reference - and, hopefully, your benefit (sorry don't remember the forum);
"Spoke to EPSON: the step I missed (and missing, too, from the step by step instructions in the manual, which was, anyway not written for 10.4) was in the copies and pages pulldown from the print dialog. That must be set to Print Settings, which then exposes a media type choice that must be set to CD.
How to print on a CD using Epson Print CD from OS X.4 Tiger:
--General cautions--
Make sure there are at least eight inclhes of free space behind the printer
Dont bend the mylar strips on the leading edge of the carrier (dont, for example, store on edge with tbhis edge down).
Step by step instructions.
(1) Design/compose your label.
(2) Prepare the printer:
(a) make sure that the guide flap for the carrier is shut before turning the printer on.
(b) make sure behind the printer you have 8 inches of space for the carrier to stick out into when printing.
(c) Turn on the printer.
(d) On the output tray side (the front) push the extension all the way in.
(e) Lift the smoked glass lid on the printer and pull down the guide flap for the CD/DVD carrier. (It doesnt matter if you then close the smoked glass cover).
(3) On the Mac ,in the EPSON Print CD application, with your label design selected, click file > page setup.
(4) on the Page Setup dialog box. set-
Settings: Page attributes
Format for: Stylus R200
Paper size: A4
Orientation: the left choice (portrait)
Scale: 100%
When these are set, click OK.
(5) Again in the EPSON Print CD menu bar, click file > print
(6) In the Print idalog box, set
(a) printer: Stylus Photo R200
(b) Presets: Standard
(c) In the third pulldown, where Copies and Pages probably appears, instead of choosing Epson CD, which would be the obvious choice, select Print Settings.
(1) The Print dialog box changes below the Print Settings entry.
(2) Set the Media Type to CD/DVD.
(3) So far as I know, the other default settings are OK (Color: Color; Print Quality: Best Photo, and the three check boxes not checked).
(7) Click the Print button."
hope it works for you and the R800