Seriously, next time just copy/paste to a text file please!
The details you've shown us so far don't really answer the questions we need answered.
So, simple questions time:
What type of tape drive do you have?
How is it attached?
The fact that it doesn't error out (every time) you do an 'mt -f /dev/st0 status' means that the system believes there is a drive, so dig through the output of the 'dmesg' command, and show us what it says please.
Simply put, it seems that your'e having one of two issues; communication issues with the tape drive, or media issues.
I'm going to assume you've already tried different media, so this leaves the first option; comms issues.
One long-haired git at your service...
