DVD Backup -- No files after job done!

I recently started using Comodo backup with Win XP Pro – 16x DVD RW Drive – DVD+R 4x media.

In the first time, when the job was done, the media had the files and I was able to read them in another DVD drive.

From the next time (with a new media everytime), backup program does the job (I see the log), but the media is just blank! Windows explorer tries to read the media for a very long time and finally shows nothing… It’s like “dvd burning session not being closed” or something like that.

BTW, I am able to burn video and other data in the same drive with Nero.

Any clue what’s going on? Thanks.