Just wanted to add...
I recently reinstalled my computer with Windows 7.
I have the Matrix Base game and the Iceberg Supernova game.
I was getting the same Direct3DX 9 problem that TaNell
was having. I uninstalled SN and put it in an adjacent directory, so they were now:
C:\Matrix Games\Armada 2526
C:\Matrix Games\Armada 2526 Supernova
Still didn't work, however, so I went to Microsoft and downloaded their 9.0c DirectX redistributable, found here: http://www.microsoft.com/en-us/download/details.aspx?id=35
after installing that, my Supernova would work.
(And then I got the 1.04 patch for SN, then the PBeM host patch, now I'm good to go again.