Can't delete TM backups from Trash

Hiya,

Im using a MacBook with OS X 10.6.2 and a Maxtor 1Tb External hdd.

I was running out of space on my External hdd, so decided to turn off time machine and delete all the backups and then do one latest backup and turn it off again, so i turned off time machine and deleted all the backups from the external hdd into the Trash.

I went to deleted the trash and after it prepared to delete some 48,000 files it came up with an error message saying:

"The operation can't be completed because an unexpected error occurred (error code -8003)."

So i researched this, tried a secure empty trash also held down the Option key and emptied the trash and also tried various different Terminal codes (I am nowhere at all competent with Terminal so i was probably doing it wrong).

I've also gone back into time machine and deleted any other backups from with time machine.

None of these have worked, and i have movies, music etc also on the external hdd so a re-format is out of the question, please help anyone!!