valid download locations

Avast Free Antivirus / Premium Security
1

When i click download on the avast website, it takes me to another website,
The URL is http://download.cnet.com/Avast-Free-Antivirus/3000-2239_4-10019223.html?part=dl-85737&subj=dl&tag=button.
Although there is an avast download link there on that URL, when i click it, opens a download dialog box and download from is from http://software-files-l.cnet.com.

Another download link http://files.avast.com/files/beta/5.0.143/setup_av_free.exe gives me 404 - Not Found page error. hence page doesnt open.

Another download link http://files.avast.com/iavs5x/setup_av_free.exe opens up a download dialog box and download from is changing. Some of them http://download806.avast.com http://ll001.avast.com http://download788.avast.com http://download528.avast.com http://download856.avast.com http://download828.avast.com

2

This is a CNET download server, all files will be downloaded from something similar…

Another download link http://files.avast.com/files/beta/5.0.143/setup_av_free.exe gives me 404 - Not Found page error. hence page doesnt open.
That is a beta, and an old one at that. It makes sense that this is so.
Another download link http://files.avast.com/iavs5x/setup_av_free.exe opens up a download dialog box and download from is changing. Some of them http://download806.avast.com http://ll001.avast.com http://download788.avast.com http://download528.avast.com http://download856.avast.com http://download828.avast.com

DownloadXXX.avast.com is an avast server. When you download it, it choses a server, and that it is where it is downloaded from. The updates also come from these servers.