It's not clear from your message if it was intentional, but you deleted Rockbox - which is why the bootloader is telling you it can't be found.
Press and hold both the MENU and SELECT buttons together for about 5 seconds, and then as you see your ipod reset, immediately press and hold SELECT and PLAY. That will put your ipod into disk mode, where you can then access it again from your computer.
If you want to use Rockbox, extract the rockbox.zip file to your ipod again, and just follow the instructions in the Database section to access your music.
Otherwise, either restore it using itunes, or run ipodpatcher again (in the same was as you did during the installation) and select the "u" option to uninstall the bootloader.