I have window vista 32, the install seems to have going ok, but getting no updates for definition or programs files,
seem to be hung up,
have try the update file that was posted here but show not for this install error code 11
Uninstall avast from Control Panel (if possible). If, for any reason, you can’t run it, try booting in Safe Mode and doing it from there. Anyway, boot after that.
Run the avast! Uninstall Utility saved on 1 in Safe Mode. Boot after you’ve run it. Repeat this for any major avast! version you have ever installed/upgraded in your computer.
Install avast! using the setup saved on 2. Boot.
Register your free copy or add the license key for Pro. Or even upgrade your key from old versions.
Check and post the results. If, for any reason, you did not solve, try doing the step 3 in Safe Mode anyway.