Driskell, I’m having the same problem. I have used OB4WP successfully on several other blogs. I am working on a new one, helping with various things, and I installed OB4WP and I get the same error.
This blog is using MySql on Apache. It’s running WP version 3.3.2. I wanted to backup this website before upgrading to 3.4.1.
I have the exact same symptoms. Installed, tried to do a download backup, and I get the same error. Activity log is empty.
I deactivated, deleted, reinstalled, and got the exact same behavior.
I deactivated a caching performance plug-in and still no luck.
Help!