A quick Google search showed me a thread that stated that the data execution prevention tool in Windows is the culprit most likely.
Right click on My computer from the start menu and select properties. You can also get to System by going into control panel. Once there click on the Advanced tab then performance settings button and then there should be a data execution prevention tab that will allow you to setup settings for your program to not be prevented from executing.
You can try installing in safe mode. Works for me when a program refuses to install sometimes.