exported spawnType is -1. I think that needs to be 0 or positive. spawntype_sel says 0, but radio buttons in gmax are 1 based, not zero based. I fixed my personal version of NwMax to account for that, but it may not be fixed on yours. What might haven happened is a default of nothing gives you a 0 instead of 1, and then it saves as value -1 during output, so -1, which won't work.
Simply change the value in spawnType to 0 and see what happens, or in NwMax, change from normal to trail, and back to normal again to correct it (hopefully).