ntop with rrd?

[stan]

I am running ntop on some FreeBSD machines, and it pretty much came up
doing what I wanted, when installed from ports without me having to twak
anything.

Now I have installed it using apt-get on some Ubuntu machines, and it
appears to not be storing hsitorical data. It does this using rrd (Round
Robin Database), and this is a plugin.

What do I need to do to get this working under Ubuntu? 

-- 
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?