DSGUI fails to load, if the order in which the include parameters have been supplied does not match what it expects.
Make sure that your includes are not defined in this order:
GUIparams: -SI../../include -C ../../etc/conf.ds -I ../otherfolder -I ../.. -ek ../../etc/evaluation.key
Instead the conf.ds and key files should be referenced first:
GUIparams: -SI../../include -C ../../etc/conf.ds -I ../.. -ek ../../etc/evaluation.key -I ../otherfolder
Note: Ensure that there are no extra spaces in the include parameters.