Time machine backup illegal name

Hi there, I've just finished setting up a new time machine backup and moving other files to my external hard drive but today i plugged it in and it wouldn't mount. I opened Disk Utility and tried to mount and repair disk but nothing has happened, all i get is errors saying illegal name and that it is unable to be repaired. I've seen that this can sometimes be caused by some adobe software but I have none installed or on that disk. I have also tried repairing it with DiskWarrior but all the options are greyed out. Here is the error by Disk Utility i get now:

Verify and Repair volume “Time Machine Backups”
Volume repair complete.

Updating boot support partitions for the volume as required.

Error: Disk Utility can’t repair this disk. Back up as many of your files as possible, reformat the disk, and restore your backed-up files.

The first time i tried repairing i got two illegal name errors. The disk still mounts in under Windows 7 but i don't want to use that.
Any suggestions?

I am running Snow Leopard 10.6.8 on my MacBook