sunburst example is not working

The sunburst example is not working.

sequences <- read.csv(
  system.file("examples/visit-sequences.csv",package="sunburstR")
  ,header = FALSE
  ,stringsAsFactors = FALSE
)[1:100,]

sunburst(sequences)

Error in FUN(X[[i]], ...) : object 'xmin' not found
In addition: Warning message:
In min(data$rects$ymin) : no non-missing arguments to min; returning Inf