Hmm..
In old ecsro server I had the same problem, and it helped me when I deleted all the stuff inside SETTINGS (In the Gsro folder)
but just to be sure, copy them somewhere else.
because I'm not sure does this help now after 3years.
So if you didn't understand: Go to your Gsro folder -> Settings folder. Copy the files, and delete them. (Or just delete them without copying) -> Start gsro
EDIT: It could be that you don't have any settings folder at all? if not, just create one. and name it exactly Setting