Installing Rgraphviz: The Rgraphviz package requires a bit of extra work beyond simply installing the package itself to run properly. The user must first have installed the GraphViz software provided by AT&T. For users of the release version of Rgraphviz from Bioconductor 1.3, this must be Graphviz version 1.10. For users of Rgraphviz for Bioconductor 1.4 (or the devel versions leading up to the 1.4 release) this must be Graphviz version 1.12. To do this: - Go to http://www.graphviz.org/pub/graphviz/ - Download GraphViz. NOTE: Please download the source and build using the sources instead of using RPMs or other prepackaged methods. - Unpack the distribution - In the GraphViz directory, run './configure', 'make' and finally 'make install'. If you have special configuration needs, specify them with the './configure'. Finally, make sure that you have the 'graph' R package installed. Once these things are both installed properly, you can then proceed to install Rgraphviz.