All those settings are not saved in the game directory.
They are all saved in the [Render] section of the $USER\Documents\Dungeons and Dragons Online\UserPreferences.ini
( in my case it's : C:\Users\Flavilandile\Documents\Dungeons and Dragons Online\UserPreferences.ini )
Code:
[Render]
AllowGammaChanges=True
AlphaToCoverage=False
AmbientLightBoost=0.00
[...]
Brightness=1.00
Contrast=1.00
[...]
Gamma=1.32
[...]
VolumetricLight=False
MaxParticleCutoffDistance=-1
MeasuredFillRate=558.43
You can edit this file using a text editor ( notepad for example, NOT wordpad though )