Has anyone else run into this problem?

The remount command failed. Maybe there is another process accessing the file system currently.

When trying to change the read/write mode for NTFS,

We have some unix files from an AIX system that we need to untar, the problem is they are on a usb drive formatted with NTFS they were shipped to us like that. We are having problems mounting to our AIX servers, so we decided to take a machine and boot from KNOPPIX, one time it works, next time you get that error message. Has anyone else run into this error message?
thanks. You cannot UNTAR it in Windows because some of the characters are not supported under Windows in the filenames. Also this is a 500GB drive and we don not have any extra workstations with this much extra space.