Problem backing up to tape

I have installed backup tape drive and Symantec Backup Exec 11 d for Windows Server as I was backing up using Windows backup to an old server.
 I have created the first backup job and ran it successfully for the first few days but then it started to the tape popped out and is asking me to insert an over writable media. No matter what amount of data I take off my selection it still asks me for a media

There are few things I am not really sure of such as:

When I do an inventory on the tape I find the following statistics when I point to the media  
Hours in Use            41.6
Data                  188GB
Used Capacity       0 Byte
Available Capacity        149 GB
Total Capacity            149 GB
Compress Ratio      1:1
Bytes Written             928 GB
Bytes Read             575 GB
Mounts             24
Seeks                  492

The job report is as follows

Byte count          : 200,416,764,090 bytes
Job rate            : 424.26 MB/Min (Byte count of all backup sets divided by Elapsed time for all backup sets)
Files               : 675,426
Directories         : 111,025
Skipped files       : 0
Corrupt files       : 0
Files in use        : 0
Original start time : 04 July 2008 22:00:00
Job started         : 08 July 2008 22:00:02
Job ended           : 09 July 2008 09:50:58
Elapsed time        : 11:50:56
          

As you can see the used capacity is 0 and still 149 GB. I am really confused. Did the backup run or I am missing out on something.