I have followed this tutorial and it works great, but only when i have one external ntfs hard drive connected. If i have two hard drives connected via usb only one shows is mounted automatically and when i try to mount the second one manually i get the error :

$MFTMirr does not match $MFT (record 0).
Failed to mount '/dev/sdb1': Input/output error
NTFS is inconsistent. Run chkdsk /f on Windows then reboot it TWICE!
The usage of the /f parameter is very IMPORTANT! No modification was
made to NTFS by this software.

I have tried this on two different computers now. Any suggestions would be very helpful. I am trying to copy files from one hard drive to the other and this is pretty impossible when only one hard drive can be mounted at a time.