I have just noticed that the avast icon on the bottom of my screen isnt spinning so I clicked on it and get this AAVM subsystem detected a RCP error, what does that mean? and what causes this? I have avast 4 and I also have anti spyware and spybot search and destroy but never had a problem with them before. I am scanning with avast and I came upon some malware and I couldn’t send it to the chest! Because of the problem up above…so I deleted it. I couldn’t do anything else and didn’t know what to do…I would like to know what is happening could it be a virus?? PLEASE help me out 
See - AAVM subsystem detected and RPC error. http://www.avast.com/eng/faq-other-questions.html#idt_1539
Check out those options to see if that resolves it.
If not - Have (or did) you another AV installed in this system, if so what was it and how did you get rid of it ?
This is often a common reason for this problem - Does the avast icon also have a Red circle with bar over the top of it ?