How can I overcome downloading issues to start using software?

I have an Apple Mac using MountainLion and downloaded Adobe Photoshop elements 10 and Adobe Premiere Elements 10. I have tried downloading using both methods suggested. I seem to have the software downloaded, but can't use it. The first method suggested was to download Akamai NetSession, which I did. However, this piece of software always gets stuck when it gets to the Destination Select as the "Continue" button always remains greyed out (as below). The second method involved downloading two pieces of software, the file itself and another, PhotoshopElements_10_LS15.exe, but when I try to open either I get the following error messages (see below). Any suggestions about how I can actually start using this expensive software?

This is really unimpressive, and it has been over 24 hours of trying without success that is making this a very frustrating experience