If it's of any help, I've just finished re-installing DB Pro and patched it with DBProUpgrade66.exe - after which programs which ran fine with the previous version of DirectX 9.0c I had installed wouldn't run.
I've know about the 300K Directx 9.0 Web setup program, but all the downloading is a pain if you have more than one computer to install it on (or like me have clients you need to install it for).
The link below is to the FULL install file for the April 2007 release of DirectX 9.0c (49.7 MB).
http://www.softwarepatch.com/windows/directx.html
I've just installed it and everything now works fine again!
TDK_Man