[R] Problem using R and Beamer...

[Jeffry Madura]

Dear [R] and beamer community,

   I am trying to build a presentation using beamer and [R].  I can Sweave the file; however, when I run pdflatex on the file i get the following error:

! FancyVerb Error:
  Extraneous input `> a = 123450 > b = -0.69 \end {Sinput} \end {Schunk} \end {
beamer at frameslide}\ifbeamer at twoscreenstext \beamer at dosecondscreennow {{fragile}
 \frametitle {Numbers} \textbf {Numbers} can be represented in a variety of dif
ferent formats. For example the number $1.2345\times 10^5$ is written as 1.234e
+05 in \texttt {R}. \begin {Schunk} \begin {Sinput} > a = 123450 > b = -0.69 \e
nd {Sinput} \end {Schunk} }\fi \ifbeamer at anotherslide \advance \beamer at slideinf
rame by 1\relax \relax \expandafter \iterate \fi \let \iterate \relax \beamer at w
riteslidentry \beamer at reseteecodes ' between \begin{Sinput}[<key=value>] and li
ne end
.
\FV at Error ... {FancyVerb Error:
\space \space #1
}
                                                  
l.91 \end{frame}

Can anyone explain to me what is going on here?  The frame code in latex is 

\begin{frame}{fragile}
\frametitle{Numbers}
   \textbf{Numbers} can be represented in a variety of different formats.
For example the number $1.2345\times 10^5$ is written as 1.234e+05 in \texttt{R}.
<<echo=TRUE>>=
a=1.2345e+05
b=-6.9e-01
@ 
\end{frame}

  Best Regards,

    Jeffry