Welcome screen cannot load configuration

[prm]

Please help
I installed Avast 4 home.
I also tried to repair it.
Actualizations go OK
Everything seamsto be OK...but
when I push the button RUN AVAST (because it's grey icon and red firbidden sing), programm gives to error massages :
1st : "System cannot open specified device or file"
        "Welcome screen avast! cannot load configuration"
2nd : "System cannot open specified device or file"
        "Simple user interface avast! cannot load configuration"

I have tried rebooting, reinstaling after uninstalling...etc
Always the same!
please HEEELP
regards
prm

[DavidR]

The red circle with bar (forbidden) sign over the avast 'a' icon may have a few causes.

AVAST FAQ - Red Circle on avast icon - AAVM subsytem detected and RPC error. http://www.avast.com/eng/faq-other-questions.html#idt_1539

If this doesn't resolve the problem it could well be down to having another AV installed or remnants of one installed, which is quite a common reason for this.

Have (or did) you another AV installed in this system, if so what was it and how did you get rid of it ?

[Lisandro]

Which is your operational system?
Any other security application that could interfere?