I know it's an old thread but it's near the top of search results when researching this problem, so I thought I would give the benefit of my experience for the next person.
I too had this problem. I am using Windows 7 Home Premium, Tackpad++ 3.0b and Parallels Desktop 9 build 9.0.24172. Launching Bootcamp with Trackpad++ set to load totally froze my virtual machine, I couldn't do anything to break out of it apart from force closing. Booting direct into Bootcamp I used the directions above to remove the driver load and now no problem under Parallels! I just have to run Trackpad++ manually when in Bootcamp proper. Strangely it didn't used to be a problem, I believe a recent software update to Parallels broke something (my version of Trackpad++ has not changed).
Another tip for you. You will see the Trackpad++ website goes on about a mandatory install of Power Plan Assistant when using 64 bit Windows. I meet the criteria for this but for me Trackpad++ installs fine on it's own, give it a go. I suspect it's a way of getting more copies of his software out there.
Last edited: Jan 17, 2014