FTE appears to be a reference to Full Time Employees - i.e. staff numbers required to administer an environment. However I have never really seen references to Backup Exec involving that terminology - I guess it is the sort of thing that is applied when trying to calculate Returns on Investment (ROIs) for why one environment is more cost effective than another, so you'd probably need to talk to our Pre-sales team about your requirements.
If you are using BackupExec for 1000 servers and 17TB, you are using the wrong product! If you are using NetBackup, your environment is greatly undersized.
That said since it's only a single server environment, a single admin spending up to 5 hours a week should be able to handle this for general tape maintenance and reviewing logs should be good. Providing the backups are successful and it's a healthy environment to begin with.
Additional time would be allocated for failed jobs and troubleshooting, upgrades, and software maintenance.
It would be wise to beef up the architechture with addtional media servers.