my problems with avast and OSX 10.7.4 have apparently dissapeared. I do not know if this is related, but just in case I tell what I did. I was having problems starting my computer, and I was said to reset my PRAM (cmd-opt-P-R) to solve that --nothing related to avast, in principle--. After that I tried again and everything worked. The program was updated (now I have 7.0 37028) and I have registered my copy without any problem.