Yes that is one of the approved/partner download sites.
Did you have avast previously installed ?
If so a clean reinstall would be best:
- Download the latest version of avast 6.0.1000 avast Free AV ( assume that is what you were installing, so try this direct download link: -
http://files.avast.com/iavs5x/setup_av_free_eng.exe (English only) and save it to your HDD, somewhere you can find it again (if you didn't save your last download). Use that when you reinstall.
- Download the avast! Uninstall Utility, aswClear5.exe
find it here and save it to your HDD (it has uninstall tools for both 5.x and 6.0.x).
- 1. Now uninstall avast! (using add remove programs, if you can't do that start from the next step), reboot.
- 2. run the avast! Uninstall Utility from safe mode, first for 5.x if previously installed and then for 6.0, once complete reboot into normal mode.
- 3. install the latest version, reboot.