tar: 0511-195 An error occurred while writing to the storage media.

tar: 0511-195 An error occurred while writing to the storage media. There is an input or output error.

The error log is always descriptive on what the problem is, so it is helpful to take a look. 
similar issues that I have seen, have been caused by the following errors:

Firmware issues: You need to look and insure you have the most up to date firmware for your drive. 
Media: Bad media can create similar issues, but this would show up on the error log. You can verify by trying a different tape. 
Cleaning: This will also show up on the error logs, but this is one of the most common problems with tape drives. 

This error can be media or tape but is generally an incorrect setting in the backup. 

File Size Issue: See if any file is over 8GB that you are trying to tar. If any individual file is over 8GB then exclude it from getting tar-ed.

Command Issue: This error occurred when you type /dev/rmto instead of /dev/rmt0 (wrongly used alphabet ‘o’ instead of digit’0’).