[R] Gantt chart problem after upgrade to R 2.4.0

[John Kane]

I am having a problem with a  gantt  chart since
moving to R2.4.0. from 2.3.1

I made some adaptations to the code from
http://addictedtor.free.fr/graphiques/RGraphGallery.php?graph=74

and successful produced a simple gantt chart.  However
when I upgraded to 2.4.0 it no longer works as
desired.  See
http://ca.geocities.com/jrkrideau/R/gantproblem.pdf
for the two charts. The charts were produced today
using the same version of plotrix (installed on both
versions of R today)

System : Windows XP 

 I am pretty new to R and especially to plotrix and I
don't see what I am doing wrong.  I have tried to play
around with the Ymd.format with no luck    Have I
missed something in the upgrade notes? Can anyone
suggest something? Thanks

My code is:

require(plotrix)

Ymd.format <- "%Y/%m/%d"

Ymd <- function(x){ as.POSIXct(strptime(x,
format=Ymd.format))}
gantt.info <- list(
  labels     =c("Dickens",	"Doyle",	"Kipling",	"Poe"),
  starts     =Ymd(c("1824/01/01", "1850/01/01",
"1865/01/01", "1815/11/01")),
  ends       =Ymd(c("1901/01/01", "1922/01/01",
"1935/01/01", "1867/01/01")),
  priorities =c(1,2,2,4))

gantt.chart(gantt.info,main="Writers",
           
xlim=as.POSIXct(c("1810/01/01","1940/01/01")))



John Kane
Kingston ON Canada