....same problem here.
BTW is the same one I had before the upgrade of my Terratec drivers.
Bad news even if u want to roll back to old windvd 4.
I did, but uninstall of Windvd platinum seems to damage something and windvd 4 didn't work anymore either.
So I take advantage of XP restore utility and I came back to the previous situation.
I made a fresh new installation of windvd 4.0 and seems a go.
I made a new restore point..and I tried "for fun" to reinstall Platinum again.
Even if Intervideo claims that the two version can lay together on the same pc when u install platinum windvd 4 doesn't start anymore. I found out that disabling Hardware acceleration on platinum solved my problems of jerky video and blocking when change chapter( I think..change type of audio out from ds to dd or dts..) and since IMHO the PQ of platinum without HA is slighty better than windvd 4 with HA on, I stopped my tests here.
ciao
alberto