Unable to back-up time machine on WD Storage Drive

I have a Macbook Pro running the most up to date version of Lion. For the first time, I have tried using time machine and time after time am getting the error "Time Machine could not complete the backup. Files can't be copied onto the backup disk because it appears to be read-only. You may need to repair or reformat the desk using Disk Utility. If the disk can't be repaid, you must use a different disk for backups. Open Time Machine preferences to select a different backup disk."

I have tried to restart, shut down, and every possible solution and get the same error over & over again. My WD storage drive is being read on my Mac because in the Time Machine preferences it is showing approx 200 GB out of 500 are available. I have only used this storage disk on my mac and no other machine.

However, On my home screen it is showing the Time Machine Backups Folder, and contains backups.backupdb folder. I then select Brett's MacBook Pro (only folder) and all dates that I have backed up are listed as folders. However, todays is an image of a blank white sheet and the file name ends in .inprogress. I have tried to delete, but I get the error that this file cannot be deleted.

Any tips on how to fix this problem so I can back-up my computer?

Did you format the drive for a Mac ?

Yes, I've only used this external drive with my Mac and have used Time Machine 20+ times on Snow Leopard no problems and am now getting this error when I am trying for the first time on Lion.

First off, id throw the WD hD as far away as you can. I have had 3 of those fail on me, within 6 months the caddys stopped working and not long after putting them into lacie caddys they drives just spewed up errors after errors.

If it means you lose not data I would format it and run Tech Tool Pro or Disk Warrior over it a few times to mac sure it is deff clean and check the actual stability of the drive…I might be jilted but WD HD have caused me nothing but pain.