To get your printer back working you need to switch your print queue to the new printer-ID-based URI. The old "usb:/dev/usb/lpX" are not valid any more for longer time, also workaround URIs of the form "file:/dev/usb/lpX" or "parallel:/dev/usb/lpX" cannot be used any more. Make sure you get a preint queue with a URI like "usb://..." or "hp://usb/...".
To do so start system-config-printer (in Oneiric click the logout/system button at the upper right, and choose "Printers" in the menu. In the main window right click the icon of your print queue, choose "Properties" in the pop-up menu, click "Change" at the "Device URI" entry. Now an auto-detection process starts and after a second or so, all USB printers which are connected and turned on get added to the list. Choose your printer and click "Apply". Now your printer's URI is updated and you should be able to print.
If your printer is an old parallel-port printer connected via a USB/Parallel adapter cable, and your printer's manufacturer and model name does not show up, try entries like "Unknown model".