First of all, I wish you all a very happy new year.
Many many thanks again to the team for delivering the v1.2 trainer so soon (my v1.2 patch download wasn't already finished !).
fatfruitcake, when are you getting your crashes ?
loading screens, (auto)saves, fighting, talking... all the time ???
I'm a Vista user too,
and I get crashes too, but in my case they are independant from the trainer.
With the trainer launched or not, The Witcher crashes quite often, mainly during the loading screens or during the autosaves.
Sometimes when I open my inventory, too...
Though (and it will perhaps help you, fatfruitcake),
it crashes a lot less often than before v 1.2.
Under the 1.1a version, the trainer seemed to amplify the crashes during loading screens.
Try deactivating the options before a transition (getting inside a house, changing zone, etc.), and reactivating them after the loading screen, and let us know if it changes anything.
For me, under the 1.1a version, it helped drastically.
I hope it will, for you too...