[R] sasweave, and R 2.5.1 vs 2.8.1

[cryan]

Looking for advice on a problem with Sweave, sasweave, and version 
2.5.1 versus 2.8.1 of R. I'm running all this on WinXP. I have both 
2.5.1 and 2.8.1 installed.

I have sasweave set up to run R 2.5.1, as this line in the runR.bat 
file shows:

set RTERM="C:\Program Files\R\R-2.5.1\bin\Rterm.exe"

And things work fine. For example, this minimal file compiles OK:

\documentclass{article}
\usepackage{Sweave}
\usepackage{amsmath}

\begin{document}

<<options, echo=FALSE, hide=TRUE>>=

setwd("C:/data/profdev/msbiostatistics/tamu/stat659/homework/homework8")
options(SweaveSyntax = "SweaveSyntaxNoweb")
@

\Sexpr{3+2}

\end{document}


But if I change to R version 2.8.1, by making the change in runR.bat 
in my sasweave directory:

set RTERM="C:\Program Files\R\R-2.8.1\bin\Rterm.exe"

then none of my \Sexpr{} expressions work. Near as I can tell, 
everything else works fine.

Anyone else experienced anything  similar, and can advise?

Thanks.

--Chris Ryan