As a Vista user, I went through the same problems and I had to search all over the place for answers. I hope you can solve your issue by looking at this one thread.
To use DBPro with Vista there are two main things, running the program as an administrator, and having Direct X 9.0c installed. Apparently Vista's more advanced Direct X version is not downward compatible to 9.0c.
To run DBPro as administrator: Right-click the DBPro icon, select Properties, Shortcut tab, Advanced button, and check the
Run as administrator box.
Click
here to download Direct X 9.0c. Installing it on Vista won't overwrite the newest version.
If the link doesn't work, then cut and paste the following URL on your browser:
http://www.microsoft.com/downloads/details.aspx?FamilyID=2da43d38-db71-4c1b-bc6a-9b6652cd92a3&DisplayLang=en
Hope this helps.
CSL