**System Information**
Windows 7 x64 GTX580
**Blender Version**
Broken: cfc109e
**Short description of error**
OBJ Crashes when empty -> dupligroup is not set
**Exact steps for others to reproduce the error**
1. open attached blend file
2. export as obj
3. crash
Expected behaviour: Not crash, this can happen halfway through exporting.
{F244321}