Class could not be found - SNAPPER analysis

[luca gregnanin]

Dear BEAST users,

I'm carrying out a dated phylogenetic analysis with SNAPPER.

I installed BEAST in a conda environment (you can find attached the packages installed along with their versions) and for the analysis I'm mostly following this tutorial https://github.com/mmatschiner/tutorials/blob/master/divergence_time_estimation_with_snp_data/README.md

I succesfully created the xml file with the ruby script, but I could not run the analysis in BEAST as I continue to get the following error:

Error 1017 parsing the xml input file

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

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

I also attach a snippet of the xml file.

Do you have any hint on why this would happen? Apparently all the required packages are already installed.

Thank you very much!

Best

Luca