Had the same problem and solved it
by genotypewriter - 10/13/07 12:45 AM
In Reply to: External Harddrive space not freeing up even after deleting by meme427
It was actually on my 2GB SD card. The amount of free space wasn't report properly. This probably happens when you remove the harddrive/device before the OS updates the file system records.
One solution is to backup everything (on to another drive) and quick format the drive. This did it for me.
Hope this helped.