I just installed Fedora 6 on my external HD but when I boot to it it comes up with error 17

I used this command mkinit --preload=ehci-hcd --preload usb-storage --preload=scsi_mod --preload=sd_mod /boot/initrd.usb.img 2.6.18-1.2798.fc6

then I put the following after the kernel in the grub.conf file initrd.usb.img is there anything I am missing