[OpenDroneMap-users] No orthophoto output

[Simon Stock]

Dear List,

I'm interested in using pictures taken with my Drone as one big 
orthophoto in GIS. So I installed OpenDroneMap on a machine running 
Linux Mint 17.2 yesterday and started playing around with the pacifica 
sample dataset.
When I use the run.pl script without any options it runs for 40 minutes 
and finishes with this messages:

- running georeferencing - Di 22. Sep 20:40:02 CEST 2015

Warning: No GCP file. Consider rerunning with argument 
--odm_georeferencing-useGcp false --start-with odm_georeferencing
Skipping orthophoto

Compressing results - Di 22. Sep 20:40:02 CEST 2015

   - done - Di 22. Sep 20:40:05 CEST 2015


When I rerun and use the suggested options (--odm_georeferencing-useGcp 
false --start-with odm_georeferencing) the script stops after just a few 
seconds with this messages:

Error in OdmExtractUtm:
No valid GPS position found
For more detailed information, see log file.
Error in Georef:
Failed opening 
/home/simon/OpenDroneMap/ortho2/reconstruction-with-image-size-2400/odm_georeferencing/coordFile.txt 
for reading.

quitting cause:
     "/home/simon/OpenDroneMap/ortho2/../bin/odm_georef" -bundleFile 
/home/simon/OpenDroneMap/ortho2/reconstruction-with-image-size-2400/pmvs/bundle.rd.out 
-coordFile 
/home/simon/OpenDroneMap/ortho2/reconstruction-with-image-size-2400/odm_georeferencing/coordFile.txt 
-inputFile 
/home/simon/OpenDroneMap/ortho2/reconstruction-with-image-size-2400-results/odm_texturing/odm_textured_model.obj 
-outputFile 
/home/simon/OpenDroneMap/ortho2/reconstruction-with-image-size-2400-results/odm_texturing/odm_textured_model_geo.obj 
-logFile 
/home/simon/OpenDroneMap/ortho2/reconstruction-with-image-size-2400/odm_georeferencing/odm_georeferencing_log.txt
returned with code 256


What am I doing wrong?

Thanks a lot,

Simon