I have noticed clients complaining of getting this error before, and at first I was puzzled.  I had just tested the installation of my application, and everything worked perfectly.  Then I realized the problem:  The client downloaded the installation package (a zip file) and tried to run the installation directly out of the zip file.  I call the client and ask them to unzip the package to a file on their desktop (just so its easy to find) and have them run the installation from the unzipped file, and no errors.