Reassociate the zip with your operating systems internal unzipper, or use "open with" by right-clicking on the file and open it with Windows Explorer. Something with the program you are using to unzip the file must be flakey.
I redownloaded 7zip because I thought it was the source of the problem. However, when I went to extract the files from the zipped installation file, I got this error:
" The compressed (zipped) folder is empty. Before you can extract files, you must copy files to this compressed (zipped) folder."