Hi Alex,
Forget that rule - it makes no sense. Both forms can be used with any type of verb. The present perfect tells us that the action or state connects both past and present so eg:
I've liked horses since I was a child. (stative verb expressing an action that has lasted from the past to the present)
I've answered twenty emails since I arrived(dynamic verb expressing some past actions which started in the past and have continued up to the present).
Continuous aspect tells us that the speaker/writer views the action as continuous but temporary. So the present perfect continuous tells us that the speaker is talking about something with past to present reference, but which s/he doesn't necessarily think is a permanent event. So eg:
I've been feeling ill for the last three days. (state)
I've been answering emails since 9 o'clock this morning. (action)
Obviously the speaker considers that sooner or later the illness will pass / there will be no more emails to answer and so chooses to present the situation as temporary.
Notice that I say "chooses to". The use of different verb forms always depends on the perception of the speaker. My favourite example of this is the following. I left England in the early 1980s and moved to Italy. After a while it was clear to me that the move was permanent and if I was talking about it, I would always say eg :
I've lived in Italy for the last ten years . However, for my mother, it was very difficult to accept that I wouldn't be returning to live in the UK, and for years afterwards she would say
Susan has been living in Italy for the last ten years. The event we were describing was the same, but psychologically I saw it as permanent while my mother went on hoping it was temporary. Hence the different choice of verb form.
For a more detailed explanation of aspect, have a look
here, and for a critique of whether there really are such things as "stative" and "dynamic" verbs, see
here.