Vista install problem

I've just received a new computer with Vista.  I've tried to install 
Shadow Plan 4.3.1 and the installer tells me,

"Catapult Install Expert could not detect a compatible Palm Desktop 
software configuration and will cancel installation."

When I tried to install "by hand" I get a pop up that says,

"No Desktop users exist."  

And, simultaneously, another pop up that says it can't 
find "Shadow.prc" (which was the file I just clicked on to get the 
message.)

I've looked all over the website and this forum for a solution.  Can 
anyone help?

Thank you.