Time Machine Errors

I have had Time Machine running since I first installed Leopard 8 days ago.  I have had no problems with it however lately I have been getting errors every hour when it tries to do a backup.  I thought well maybe the permissions were messed up and went into Disk Utility to repair them.  Disk Utility would not allow me to verify or repair the permissions.  I am not sure what is going on with this.  Have any of you readers seen this happen to you?  I tried to get Disk Utility to just repair the disk because it seemed to have issues when I ran verification however it will not unmount the disk.

I am not sure what happened with Time Machine however I have fixed it.  For some reason it was saying that it could not find the backup volume when i changed the drive and then changed it back quickly so that it would use the same drive.  I formatted my backup drive and started time machine over from scratch.  I hope that this does not cause any other issues and Time Machine should be smart enough to see that I have deleted the old backups.  It is running the initial backup again now so we’ll see how things go.  I hope this does not happen often because when you delete your backups what is the point of such a program?