discrete mugration: java.lang.Error: randomChoiceUnnormalized falls through -- negative components in input distribution

[MordorianGuy]

I am trying to run the discrete mugration model with the package following the tutorial. I did the model construction in BEAUTi word-by-word but got strange results. Actually, the results, trees & logs turned out normal, according to the tutorial. However, I caught the following in stderr:

Warning: removing transform class beast.base.inference.operator.kernel.Transform$LogConstrainedSumTransform because it should have at least 2 dimensions but it has 0
Turning on scaling to prevent numeric instability 1.0201
…
0	NaN
1	NaN
2	NaN
3	NaN
4	NaN
java.lang.Error: randomChoiceUnnormalized falls through -- negative components in input distribution?
Please report error to Marc

You may find all files here

I see such the first time and do not understand the reason. Moreover, I have compared my XML with the example from the package GitHub repository and did not detect the difference, of course, besides new BEAST 2.7 default operators. I tried to run the example unsuccessfully; it falls with:

Error 1017 parsing the xml input file

Class could not be found. Did you mean beast.base.inference.MCMC?
Perhaps a package required for this class is not installed?

Error detected about here:
  <beast>
      <run id='mcmc' spec='MCMC'>

May this error influence the results of real analyses? How to correct my XMLs to eradicate it?