I've got the exact same problem:
Trying to open the Pixel Bender Toolkit, it immediately closes after initiation. No message whatsoever.
I hadn't used the plug-in for a while, I have changed my graphic card to an unsupported NVidia card. But the Pixel Bender filters do open in Photoshop CS5(12.0 64-bit), although new filter don't seem to show up (but that might be a different issue)
I've managed to get it to work in compatability mode with 256 colors. Quite useless because I'm unable to see what I'm doing, although It does allow me to edit the code.
It unfortunately seems to me that you need an outdated graphic card to still use Pixel Bender Toolkit.