Dibbler (me again)

Hi.
So I've set up our network with an IPv6 address : 2001::X and set up
dibbler, the client works fine on Fedora Core 4.
My first question is how do I execute a command so that it gets an address
automatically at startup. I've tried putting the command in
rc.local(because the user is root) but nothing happens.
 My second question is about the dibbler client on Windows. I've tried
setting it up with the normal client config file but when I start the
service, it says it got stopped. Is there anything special I have to do to
make it work?
 Third question is, I've heard Dibbler doesn't give prefix with the address
it sends, so when I run the client on FC4, I get an address with a /28
prefix. My Debian server can still ping it, but I'm wondering if I can
change that.
 Thanks :)