[BioC] Rgraphviz and graphviz on windows pc's

[ravi]

Hi,
I have graphviz v2.21 installed along with R 2.8 and Rgraphviz. I am
not able to get Rgraphviz to function, on win XP and Vista pc's.There
has been a lot of discussion on this, both in the bioconductor and the
R mailing list. I would like to know what the current situation and
recommended procedure is.
I get the error message that cdt.dll is missing when trying to load
Rgraphviz in R. Also, the following output :
> library(Rgraphviz)
Loading required package: graph
Loading required package: grid
Error in inDL(x, as.logical(local), as.logical(now), ...) :
  unable to load shared library
'C:/Users/Ravi/R/win-library/2.8/Rgraphviz/libs/Rgraphviz.dll':
  LoadLibrary failure:  Det går inte att hitta den angivna modulen.

The sessionInfo command gives the following output :
> sessionInfo()
R version 2.8.0 (2008-10-20)
i386-pc-mingw32

locale:
LC_COLLATE=Swedish_Sweden.1252;LC_CTYPE=Swedish_Sweden.1252;LC_MONETARY=Swedish_Sweden.1252;LC_NUMERIC=C;LC_TIME=Swedish_Sweden.1252

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

other attached packages:
[1] graph_1.20.0

loaded via a namespace (and not attached):
[1] cluster_1.11.11 tools_2.8.0

What is the solution to this problem. Should I switch to an earlier
version of graphviz? Where do I find it? Should I add something to the
path in the environmental variable list?
Thanking You,
Ravi