My avast Free registration expired last month. when I tried to register, there was a pop-up "The AAVM subsystem detected a RPC error. What is RPC error and what should I do to fix it?
What version of avast are you using 7.0.1426 is the latest ?
What is your operating system ?
This error message in earlier versions of avast was synonymous with having another AV installed or remnants of one on your system. Have (or did) you another Anti-Virus installed in this system, if so what was it and how did you get rid of it ?