cd-rom usb problem

[einna]

hi everybody!!

i have a cd-rom reader with burning cds for usb link to my laptop.

when i try to run knoppix (all the 3.X versions) it can read it, but later it's not working.
i can see it its icon on the desktop, with my 2 partitions and my floppy disk. all works less my usb cd-rom.

i can read this type of message:

"cd1 not found in file:/mnt"

any idea??

un hola hola from spain