I just off the phone with Epson and one problem with Leopard is that it uses Apple's drivers for printing instead of Epson's. I couldn't print directly to CD because of that. Even when I used DiscCover or Disc Label, the formatting was all wrong even with calibration.
To see if that's your issue, go into system setting -> printers & faxes and then select the Epson printer from the menu. On the right, it will give information about your printer including KIND. If it has your printer name followed by GUTENBERG, that means it discarded the epson drivers in favor of the Leopard ones when you upgraded from Tiger or when you installed the printer.
You have to delete that printer (hit the minus button while it is highlighted). He then had me go to Macintosh HD-> Library->Printers and delete the entire Epson folder to prevent it from automatically reloading... this may be overkill, but...
Next, REBOOT.
Then go to Epson.com and download the latest mac drivers for your printer and install them. Go back to System Prefs->Printers and Faxes and click on the + button to add a printer.
When I did this it, my r1800 came up, but it had a drop down menu to choose the KIND and it still had the Gutenberg option, but it now had 'EPSON SP 1800'-the actual epson drivers. I chose that option and now it works flawlessly and I can again print to CD.