the emc2 group is working on a real time kernel for dapper.
there is a note here
http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl/
about it.
If you want to test - they might be able to walk you through setting up the correct kernel on irc.freenode.net channel #emc
Other wise the easiest is to just use breezy and follow the directions for it here.
http://wiki.linuxcnc.org/cgi-bin/emc...nstalling_EMC2
option 1
(painless)
sam