Error: This installation package could not be opened.

[topgearfan]

This error occurs immediately after I open the installer package.
How I got to this point:
I wrote the image file onto a DVD.
When I tried to run that version, I got the error: The system cannot read from the specified device.
I copied the files from the DVD to the hard drive.
When I tried to run this version, I got the error: This installation package could not be opened. Contact the application vendor to verify that this is a valid Windows Installer package.
Any help is... well... helpful.
Any questions I will try to answer.
Note: I am running Windows 7.

[Renard]

Hello!
Please check if the ISO file was downloaded correctly (no error) by running a MD5 sum tool. Details are provided on the download page.

Thanks!