[R] problem wih plotrix:cluster.overplot

[Jean Véronis]

Hello,

I am trying to use cluster.overplot from package plotrix and I get an error message when I add the "away" parameter:

require(plotrix)
distance <- read.table("distance.txt")
cmd <- cmdscale(distance)
cp <- cluster.overplot(cmd, away=2)

Error in if (sum(overplots) > 1) { : 
  missing value where TRUE/FALSE needed

If I don't use "away", everything works fine.
I don't see anything in the documentation that explains this error.
Any help will be appreciated.

Many thanks
--j