afaik, rendering jsf into a portal requires different things than rendering into a single webpage. You could have seen found that by all the questions there were related to jsf and portals.
And btw, nothing changes your life only for the better. Everything has its downsides. ICEFaces is nice when used separately. In combination with Seam it it not there yet, but making advancements.
It's nothing to worry about. ICEfaces is simply checking for portlet classes and not finding them, so it will treat your app as a non-portlet-based app. I'll log a bug at ICEfaces to generate a less unsettling debug message.