2.5.47-xfs loop device problem

The patch fixed the oops I got previously. But I still get this error :

spam michael # mount -o loop stuff/linux-cd/knoppix/orig/KNOPPIX_V3.1-08-11-2002-EN.iso /mnt/iso /dev/loop0: Input/output error
mount: you must specify the filesystem type

dmesg output :
Buffer I/O error on device loop(7,0), logical block 0 Buffer I/O error on device loop(7,0), logical block 1 Buffer I/O error on device loop(7,0), logical block 2 Buffer I/O error on device loop(7,0), logical block 3 Buffer I/O error on device loop(7,0), logical block 4 Buffer I/O error on device loop(7,0), logical block 5 Buffer I/O error on device loop(7,0), logical block 6 Buffer I/O error on device loop(7,0), logical block 7 Buffer I/O error on device loop(7,0), logical block 8 Buffer I/O error on device loop(7,0), logical block 9 Buffer I/O error on device loop(7,0), logical block 10 Buffer I/O error on device loop(7,0), logical block 11 Buffer I/O error on device loop(7,0), logical block 12 Buffer I/O error on device loop(7,0), logical block 13 Buffer I/O error on device loop(7,0), logical block 14 Buffer I/O error on device loop(7,0), logical block 15 Buffer I/O error on device loop(7,0), logical block 0

Thanks.