[X4U] LaCie Hard Drive problem

[eleventhvolume]

I wonder whether anybody can advise on my problem - I've used a 40gb LaCie
pocket drive as a backup disk for at least three years without problem. I
now find that Carbon Copy Cloner is unable to back my Powerbook drive onto
the LaCie because it says the disk is full. The Finder confirms that there's
only 2mb free. However, my Powerbook drive has only 31gb used with 43gb
available. I've used Disk Utility to erase the free space on the external
drive, to repair permissions and to repair the disk. I'm still told that
27gb are used and only a few mb are available.

Can part of a drive become unavailable permanently and is this what's
happened and is there something I can do about it?

Thanks for any help anybody can provide.

All the best, Colin.