rox-session 0.30-r2 comes up with two dialog boxes. The one towards the middle of the screen says :"your window manager has crashed" and the one in the upper left corner has a Python script error. I'm going to attempt to capture some of this stuff.
I haven't been able to get much of it to work. Apparently it's trying to go out to the web site and download its own window manager, OroboROX. I'm on an AMD 64 and OroboROX is masked on that platform in Portage, so I can't load that version. Even if I could, the upstream looks "testing level" at best. It's pretty much useless without a window manager -- the windows come up but you can't move them around.
Ah yes, I see the problem. It tries to automatically start the first window manager it can, and since rox-session-0.30-r2 relies on 0install now, it sees '0launch' and tries to download oroborox, which is the old ROX desktop default (that was never really finished, and *is* actually available in portage). I've written a patch that lets you choose from a set of window managers, or specify your own, and won't start Oroborox unless you ask it to. Please let me know if your favourite window manager is missing from the list. First be sure to remove the file ~/.config/rox.sourceforge.net/ROX-Session/Settings.xml Then please try rox-session-0.30-r3 (should be hitting the RSYNC mirrors soon). By the way, thanks for your patience with these new testing versions of rox-session - I'm working off a previous install so I didn't ever encounter this which only happens if you haven't previously configured a window manager for rox-session.