[R] Sweave PDF files show plot symbols as "q"

[Allan Engelhardt]

I'm guessing this is a FAQ but I can't find it and that it is probably 
not exclusive R related but relevant so I thought I'd ask:

When I view the PDF output from Sweave (e.g. Example 1 from the author's 
web site at [1]) on a Linux system using the standard PDF viewer [2], 
the circles for the outliers in the plot [boxplot(Ozone ~ Month, data = 
airquality)] show up as the letter 'q'.

I have no problems with the PostScript version of the file 
(example-1.ps) and I have no problems with the PDF file on a Windows 
machine using the Acrobat reader.  Also, odfWeave is consistent on all 
systems.

I need to generate reports from R that work (=look the same) across 
platforms: does anybody have a suggestion for a workaround?

Regards

Allan


[1] http://www.statistik.lmu.de/~leisch/Sweave/example-1.pdf
[2] GNOME Document Viewer 2.28.2 from evince-2.28.2-2.fc12.x86_64

 > sessionInfo()
R version 2.11.0 (2010-04-22)
x86_64-unknown-linux-gnu

locale:
  [1] LC_CTYPE=en_GB.UTF-8       LC_NUMERIC=C
  [3] LC_TIME=en_GB.UTF-8        LC_COLLATE=en_GB.UTF-8
  [5] LC_MONETARY=C              LC_MESSAGES=en_GB.UTF-8
  [7] LC_PAPER=en_GB.UTF-8       LC_NAME=C
  [9] LC_ADDRESS=C               LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_GB.UTF-8 LC_IDENTIFICATION=C

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

other attached packages:
[1] fortunes_1.3-7 ctv_0.6-0