My Western Digital Studio won't back up anymore

My Western Digital Studio drive keeps having Time Machine backup failures. Latest error says: error in creating backup folder. I have been using this drive for over a year with no problems. Tried fixing using both Disk Utility and Disk Warrior. Have erased and reformatted. Have installed latest drivers from WD (Turbo + for Mac). Still having problems. Have posted to WD discussion forums but have gotten no relief. Any others having this problem?