How are you installing it? 

 

If it is an iso file that you have attached to a VM etc... then redownload the iso file. it has become corrupted.

 

If you have made a USB drive or cd from an iso file, try remaking them. If that fails, then download the iso file again.

 

I hope that helps. If you have any further issues let me know. happy to help.

www.000webhost.com