Yes, I have same problem following the last AV update Avast now reports Cerberus on my Galaxy S4 as a trojan and disables the app. Consequently I cannot use Cerberus features remotely while Avast is installed. Though I have reported this as a false positive to Avast there does not appear to be any way of instructing the Avast to ignore the percieved "threat" and allow Cerberus to run properly.
Avast forums have not so far been very helpful and indeed Avast technical support seems non-existant, even the button (link) to raise a support ticket causes a "page does not exist" error!
It seems I really have no choice except to unistall Avast until they have acknowledged the problem and issued a fix, shame that I have to choose between software security or hardware security but since my phone was quite expensive I have to go with the latter.
Neither of these apps are the free versions and it is a pity that developers cant work together to ensure their apps are compatible with other security apps! Cerberus is a superior product which has served me well in the past whereas, alas in practice, Avast is found to be lacking in its inability to correctly identify and distinguish real threats from essential apps nor does it currently have the ability to flag such apps as ok and ignore them when it's made a mistake. Shame I paid for it before I was aware of the issue. Maybe someone can come up with a better answer or a fix. :-((