I would be opening a call with Symantec (they still own BE?). The abort detected occurs right after the line. I can't find anything on the error number 0xfffffdfd that relates to your issue. Is this the same error no matter what the backup fails on?
If you change the drive I would also change the cable at the same time but if you have a spare its probably worth trying but if it does not work are you able to use that as your backup device for some time? You don't really want to shut the system down to test it and then have to shutdown again to change it back in quick succession. Better yet can you connect both drives at the same time?