[BioC] Problem whith Rgraphviz

[Jeff Gentry]

> download graphviz 1.12 from AT & T website. Somehow
> Rgraphviz works nice with graphviz verion 1.12
> and configure using below path. 

It also works with Graphviz versions much more up to date then 1.12 :)

That being said, I received an email over the weekend indicating that they
were having trouble getting Rgraphviz to work against the new Graphviz 2.2
so the OP's email appears to be a confirmation of that.  I'll take a look
at it.

I would recommend using a slightly older version of Graphviz (eg 2.0)