Happened to me too on my new site just this morning. It didn't create the archive files but DID wipe out my wordpress directory completely with the exception of the wp-content folder. OUCH! This sets me back hours of work now.
Hosting environment: Linux - kernel v.126.96.36.199-grsec-sg2
WP version : 3.05.
Final message of the site:
1. First we need to gather some information about World Solutions
Don't worry, sit back and I'll do all the work.
2. Get the required database information.
* DB Host: localhost ✔OK DB Name: worldsol_wrdp1 ✔OK
* DB User: worldsol_wrdp1 ✔OK DB Password: [Hidden] ✔OK
* Website URL: http://worldsolutions.us ✔OK
* Get Full WordPress Path: /home/worldsol/public_html/wordpress ✔OK
3. Now let's get the database contents and create World_Solutions_2011-02-23.sql
* Archiving Your Database ✔OK
4. Finally we'll zip your entire WordPress installation and the database into World_Solutions_2011-02-23.tgz
Oops! Something went wrong. Please deactivate EZPZ One Click Backup then reactivate it.
of course, the site wouldnt work at all after that....
now root says: Fatal error: require() [function.require]: Failed opening required './wordpress/wp-blog-header.php' (include_path='.:/usr/local/php52/pear') in /home/worldsol/public_html/index.php on line 17
...probly cuz it's missing the folders and files in the wordpress folder.