Time Machine won't backup

[centurion]

I have a 20" IMac X10-5.6  2.4GhZ intel core 2,  4Gb memory connected via firewire to a 500 GB Western Digital "My Book" external hard drive.  All was well until I disconnected without closing down. Now when I attach the hard drive, I get an orange icon labeled "Time Machine Backups" on my desktop.  When I open Time Machine to turn it on I get this error message "You do not have appropriate access privileges to save file ".001f5beed9b5" in folder "Time Machine Backups"
Any HELP or suggestions would be much appreciated.    Hank

[fivespan]

Here is a hints documents that has a "terminal" solution and a "wipe the external drive" solution:

http://forums.macosxhints.com/showthread.php?p=515083

If you want to salvage the backup, don't use the wipe external drive solution! If you want to use the terminal solution, every keystroke counts.

pault

[centurion]

Thanks fivespan,  I erased and reinstalled. It worked .   Thanks.