After a power loss (covered in this topic https://www-secure.symantec.com/connect/forums/errors-after-power-loss) I have the tape drive recognized. I'm now getting this error:
"e000846b - The resource could not be backed up because an error occurred while connecting to the Backup Exec for Windows Servers Remote Agent. Make sure that the correct version of the Remote Agent is installed and running on the target computer. For additional information regarding this error refer to link V-79-57344-33899".