upgrading to Nero 7 broke my WinDVD5 install

[shAf]

I upgraded from Nero 6 to Nero 7.5.9 this weekend, and now my preferred DVD-AVI player, WinDVD5, doesn't work properly. It will play a DVD properly, but it will not show the picture for an AVI. Instead it will show "pretty colorful patterns" similar to a lightshow.

What did I do wrong?

WinXP (SP2)
ATI AIW 9700P

TIA