Error in plotting the Bayesian skyline plot 

I can't generate a Bayesian skyline plot in tracer, due to the following error "Fatal exception during initializing group size: Group size 0 should be integer but found: 24755.704424064254". I saw in other posts that the problem could be a different number of states in the log file and the tree file, however both are logging each 5000. Could this error be for another reason?