I followed the instructions as per:
http://kdenlive.org/user-manual/downloading-and-installing-kdenlive/pre-compiled-packages/ubuntu-packages

and Instead, I get:
W: GPG error: http://ppa.launchpad.net natty Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY B5115B98AA836CA8

btw: I did the exact same as above in "Kubuntu 11.04" and everything went fine.

To Moderators of this Forum:

btw, can we now stop with all this double and triple cryptic looking word notifications everytime i want to simply post a topic/reply/.../.whatever ?!

It should be more than enough that ppl are bugged about 1 word notification at login to this forum.
It almost as if you don't want ppl posting to your forum
:)

Cheers.

ok, well I found this and it worked thx.
and actually the above gpg error is from "UbuntuStudio 11.04"

wget -q "http://keyserver.ubuntu.com:11371/pks/lookup?op=get&search=0xB5115B98AA836CA8" -O- | sudo apt-key add -

To kdenlive:
This should have its own topic, but kudos to all the ppl workin' on "kdenlive"
It is, bar none, the best NL Video Editor in Linux. ! And I still believe Sony's "Vegas" was stolen from kdenlive
;)

I'm torn between "Kubuntu", "UbuntuStudio", and Arch, as distros of choice for kdenlive, but that's about my only quirk. I've heard good things about opensuse, but I like my debian, and BSD/Unix styles too much still.
Unfortunately "Unity" in Ubuntu sucks. :(
Now, if they ever came out with a "KubuntuStudio", AND an "ArchStudio" just for kdelive, then wow, -just for me ?

anyway, thx, and keep up the great work.