You are correct. The file available is an Avira registry cleaner.
I actually ran this cleaner on my system to see what it would find and do. Many, many, registry entries found that had nothing to do with AntiVir 9. See attached removal log below.
As this machine was once in corporate use, most entries found were in a Domain location, and also seemed to have many entries for rogue antivirus programs in there as well.
For your purposes, only tick those entries for removal that have anything to do with AntiVir antivirus, and no other. The point here is to cause no harm to your system. Note also any reference to Avast! was not removed.
Either the avira_registry_cleaner_en.exe or the .zip file will work. NOTE: (TIP) Whenever a .zip file is run or extracted, the extraction process will always produce more files and folders, and can become a mess if extracted to the desktop. Always create a new folder and place your .zip file inside that new folder. That way, any extracted files/folders will stay within that new folder. No mess and makes it easier for you to find it later.
If, in the past, you know of another a/v program or two once installed, use the singularlabs to finalize removal of these programs, if any.