The most likely cause of this is that the file has not been downloaded in full and the zip is corrupt.
You will need to download the File again, if you use all of your 3 download attempts and are still having problems, contact us via Contact form.
For the best chance of success we recommend that you:-
1. Delete fully the file/s downloaded so far which were incomplete and empty recycle bin
2. Restart your machine and clear your cache
3. Ensure you have a good, constant connection to the intenet.
4. Choose to save to a local rather than removable drive
5. do NOT use download acceleration software - it will not work