Problems with G-Drive and Time Machine

I just replaced a 1TB external G-Drive with a 2TB G-Drive on my Intel Mac Pro with 10.7.5. I use the G-Drive as my Time Machine backup. The original 1TB drive worked fine with no problems. The 2TB drive worked fine for a day or so. Then I got an error message from Time Machine saying it could not complete the backup up because it could not create a folder on the G-Drive. I tried copying a file from the desktop to the G-Drive without using Time Machine and I get an error message saying it could not access the drive (error-50). I then discovered I could not eject the drive. Had to do a force eject.

I then used Disk Utility to try to do a repair but continued to get the same error from Time Machine. I erased and reformated the disk, force ejected it, and restarted. Time Machine worked after that but only for a few backups. Now I am getting the same error.

I contacted G-Drive who say this is a known issue with Time Machine and not a problem with their drive. I called Apple support. Their knowledge database does not show any issues with Time Machine and G-Drive.

I am not sure if I have a defective drive or if the drive just won't work with Time Machine. Has anyone had the same problem? If so, were you able to solve it and how did you?

Thank you.

Bruce