Note:

This problem was fixed with Service Pack 0, released in May 2012. Please check, if your Avira product is up to data and perform a product update if necessary.
In case, this problem persists, please contact our support team, referencing to article Id: 1076.

With very high adjusted security policies of the system it can happen that the displayed Avira messages can not be closed because the „Close“ button is deactivated.

To change the explained behaviour do the following adjustment on your system:

1. Click Start → Run , type regedit, and then click OK
2. Expand the following registry subkey
   HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones
3. Delete the extra (parasite) zone from the Zones subkey
   Note: The parasite zone is a pseudo-graphic number listed before zone number 0. The pseudo-graphic number looks like a miniature upper case "L"
4. Close the registry editor

Alternatively you can use the Microsoft Fix it 50618 programme to correct the security policies of the system automatically:

http://support.microsoft.com/kb/2506343/en-us#FixItForMeAlways