It seems gnome-open belongs to Gnome 2, while gvfs-open is the Gnome 3 equivalent....
Did you compile Ipe yourself? In that case, it's your responsibility to set prefs.browser...
7.1.7 does not honor prefs.save_as_directory
Order of objects in the LaTeX run
IPE 7.1.7 does not even start under Windows Vista (because of missing GetGestureInfo)
IPE 7.1.7: Ipelet "Move" - shortcuts not working
[Ipe 7.1.7] On windows, labels are missing from document properties
[7.1.7] Missing images.lua (Mac OS X)