According to a Google search, Tpkd.vxd is part of PACE Interlock software protection. You probably need to know what application installed this driver. Was this the protection scheme they had on the early versions of Poser 5? I don't have Poser 5 but I seem to recall that the copy protection caused stability problems for some people. If that's it, I imagine you need to get the latest Poser 5 updates.

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken