I figured out the problem. The reason is that the adjustment fails and some values becomes
NaN (Not a Number). This is already mention by the stack-trace of the error message - see my attached screenshot and the marked line. I will fix the
NaN value within the next release but this fix will not solve your problem. Currently, your network is incorrectly configured. For instance, each set of directions requires observations (directions) to at least two different points, because two directions define a single angle.
To get a better impression, please take a look to this example. The example contains one distance group and three sets of directions.