I made another script. First go to link and, if u didn't already, authorize application. After you authorize on youtube it will show all your uploaded videos.
Then you choose which ones to edit.
Then you will see textboxes with current Titles, Descriptions and Tags which you can edit now.
If u want same description for all videos then just type it for the first video, click "copy" next to it and it will copy to all others relevant descriptions. ie Titles->Titles, Desc->Desc and so on...
Click submit and walla, it's done.

link: www.fumusic.net/videoedit.php

It's pretty ugly, but it works.
Please post any errors and wishlist here, enjoy