Avast was blocking because it was finding HTML:Iframe-inf there aka HTML:Iframe-inf
see: http://support.clean-mx.de/clean-mx/viruses.php?descr=NationalNet,%20Inc.%20NATL%201130%20Powers%20Ferry%20Place,%20SE%20Marietta%20GA%2030067&sort=first%20desc&response=alive

polonus