cvs co -r release_eta_carinea_rc1 tiki This will place the latest 1.7.x code in a directory named "tiki".
cd tiki cvs -q update -d -r release_eta_carinea_rc1 Beware of conflicts. It may be easier to simply checkout a fresh copy of the code
cd tiki cvs ci There is no need to specify the branch if you checked out using the instructions above
Remember to set your ENV variables correctly: export CVS_RSH=ssh export CVSROOT=:ext:youraccount@cvs.sourceforge.net:/cvsroot/tikiwiki
For more information, see CvsForDevelopers.
You can also submit patches here: http://sourceforge.net/tracker/?group_id=64258&atid=506848