[R] error with sendplot

[Straubhaar, Juerg]

I am trying to use  heatmap.send() in package sendplot with the example data given in 'A tutorial for sendplot R package', Section 4.

The code I am using (copied from tutorial) is:

data(mtcars)
x <- as.matrix(mtcars)
xy.labels=list(value=x)
x.labels=data.frame(label=colnames(x),
    description=c("Miles/(US) gallon","Numberof cylinders",
        "Displacement (cu.in.)",
        "Gross horsepower",
        "Rear axle ratio",
        "Weight (lb/1000)",
        "1/4 mile time",
        "V/S",
        "Transmission (0 = automatic, 1 = manual)",
        "Number of forward gears",
        "Number of carburetors")
    )
rc <- rainbow(nrow(x),start=0,end=.3)
cc = rainbow(ncol(x), start=0, end=.3)

heatmap.send(x,scale="column",xy.labels=xy.labels,x.labels=x.labels,
             RowSideColors = rc,
             ColSideColors = cc,
             margin=c(5,10),
             xlab="specification variables",
             ylab="Car Models",
             main = "mtcars data",
             fname.root="exHeat",
             dir=".",
             font.size=18,image.size="600x900")

Unfortunately I get the error:

ERROR: could not map. 
       one of the required tif files is not found 
       Missing either  .exHeatDot.tif  or  .exHeat.tif 
Error in boundingPt$up.left : $ operator is invalid for atomic vectors

sessionInfo()
R version 3.0.2 (2013-09-25)
Platform: x86_64-pc-linux-gnu (64-bit)

locale:
[1] C

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] sendplot_4.0.0 rtiff_1.4.4    pixmap_0.4-11 

loaded via a namespace (and not attached):
[1] KernSmooth_2.23-10 bitops_1.0-6       caTools_1.16       gdata_2.13.2      
[5] gplots_2.12.1      grid_3.0.2         gtools_3.3.1       lattice_0.20-27   
[9] tools_3.0.2       

Thank you.