The red cross in the 4.8 icon is sign that the antivirus is disabled.
Some other application is preventing the correct install of avast.
But if you follow the steps again (uninstalling the other antivirus first), post back the error occurred in step 5.
Well, as i said i had installed the newest version of avast earlier today (5.0 something), it was not 4.8 anymore.
And yes, i completely understood that the red cross is the sign that something is wrong. But why oh why is the avast sign also red? A RED cross on a RED avast sign. Very difficult to notice in a glance that something is wrong, unless you watch it all the time. That surely is not what a customer wants.
Some other application is disturbing the installing process yes, but which one, that is the question. Now that i have a working virus scanner I'm not going to test this problem any more, sorry.