--- Operating System, Graphics card ---
Linux SuSE 12.2 (x86_64)
NVidia GTX560ti (official driver)

--- Blender version with error, and version that worked ---
2.66a r55057 works
2.67 r56533 doesn't

--- Short description of error ---
In the compositor only, deleting Group Output node in a nodegroup then tabbing out causes Blender to segfault. Nodegroups in the texture/material systems are unaffected.

--- Steps for others to reproduce the error (preferably based on attached .blend file) ---
- create a basic nodegroup in the compositor - initial nodes must be connected to the Composite output node before making the group
- within the nodegroup, delete the Group Output node, then tab out