Since only the dotLRN core is fully ported right now, you want to be sure that that is all you install over the basic OACS install with the package manager if things are to work properly.
So when in the APM, you should uncheck all *-portlet packages, and all dotLRN packages EXCEPT: dotlrn, dotlrn-portlet, and dotlrn-applet.
If you do that, all should go well, and you should get the plus sign (+) next to dotLRN after you mount it in the site-map and restart your server.
--dan
