ZoomIt - Error launching 64-bit version: This program is blocked by your group policy.

Zoomit doesn't work on a 64-bit machine with certain group policy settings.
In my situation, when you run the downloaded zoomit.exe, it tries to create a 64-bit version in the folder specified by the TEMP variable. Writing to the specific temp folder is blocked by group policy.

So the solution was to create a new folder C:\Temp1 and change the TEMP variable to C:\Temp1  - this fixed the problem.