Help Unable to install VISIONary + on my DHD

Hi there. I am new here, and I am not sure whether I am asking a silly question as I am unable to find them in the web. By the way I am noob. Lol. Well, here goes..

I was unable to install VISIONary +, got from this site: 19/Nov r14: VISIONary + one click root - Android @ MoDaCo

I download via pc, send it to my DHD, open the file, click install, and it says "Application not installed". Tried via HTC Sync too but cant.

Is there any possible reason for this "unable to install" problem?
Permission states: "System tool: automatically start at boot". Is there anything I got to do with this first before I can install it? Again, me noob. Lol. Cause normally whenever I want to install any apps, the color will be red, but this is instead white color. I am using version 2.2

Any possible reason and solutions will be much appreciated.