cannot find what consumes external hdd space?

My father in law's mac has an external LaCie hdd. In terminal, when I run df -h i get:

"/dev/disk1s6 233G 203G 30G 87% /Volumes/LaCie"

when i go to /Volumes/LaCie and i run du -hcd 1 i get:

"nxxx:/Volumes/LaCie mac$ du -hcd 1
du: ./.Spotlight-V100/.journalHistoryLog: Permission denied
du: ./.Spotlight-V100/.store.db: Permission denied
du: ./.Spotlight-V100/_rules.plist: Permission denied
du: ./.Spotlight-V100/ContentIndex.db: Permission denied
du: ./.Spotlight-V100/store.db: Permission denied
du: ./.Spotlight-V100: Permission denied
0B ./.TemporaryItems
du: ./.Trashes: Permission denied
272K ./2008-09-02-MyBackup-01
57G ./2008-12-07-MyBackup-01
0B ./Desktop
18G ./iPhoto Library
1.1G ./My Documents
77G .
77G total
nxxx:/Volumes/LaCie mac$ "

The df utility shows that the mac is using 203GB whereas du shows the mac is using 77GB. What is consuming the other 124GB?

Try a sudo du -sch /Volumes/LaCie

or the -hcd will work too..

That still returns with 77G. I am looking for a file or folder which is consuming 124G. I think the file or folder might be hidden but even hidden files should be picked up in du.
Any ideas? Can it be that the external hard drive might be confused?

Almost sounds like there's either a hidden partition on the drive or the partition table is messed up. I can't imagine a hidden file or folder of 124 Gb in size. What file system is the drive using?

Regards.