On Windows, whenever one executes a line of R code the kernel breaks and has to be restarted. The problem is IMHO two-fold:
As a temporary fix I convert all backslashes to forward slashes:
self.r('png("%s/Rplots%%03d.png",%s)' % (tmpd.replace("\\", "/"), png_args))
Have you got rpy2 working correctly on Windows? I thought that was currently an obstacle.
It's not so much, there is even a binary installer over here: https://bitbucket.org/breisfeld/rpy2_w32_fix/issue/1/binary-installer-for-win32
Just follow the instructions. You might need to fix the file of rpy2 that finds the binaries though, as it doesn't append your arch to the bin-path (that reminds me, need to report that ...)
Well, I'm glad to see someone's working on it. (To be clear, I don't need it myself, though)