Error(s) in re-building vignettes:
--- re-building 'fastJT.Rnw' using knitr
Warning in system(paste(shQuote(texi2dvi), if (quiet) "--quiet" else "",  :
  running command '"C:\PROGRA~1\MiKTeX\miktex\bin\x64\texify.exe" --quiet --pdf "fastJT.tex" --max-iterations=20 -I "C:/r_packages/rinst/share/texmf/tex/latex" -I "C:/r_packages/rinst/share/texmf/bibtex/bst"' had status 1
Error: processing vignette 'fastJT.Rnw' failed with diagnostics:
running 'texi2dvi' on 'fastJT.tex' failed

LaTeX errors:
fastJT.vrb:5: LaTeX Error: Command \item invalid in math mode.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...                                              
fastJT.vrb:5: LaTeX Error: Something's wrong--perhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...                                              
fastJT.vrb:5: LaTeX Error: Something's wrong--perhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...                                              
fastJT.vrb:14: LaTeX Error: Command \end{beamer@framepauses} invalid in math mo
de.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
fastJT.vrb:14: LaTeX Error: Something's wrong--perhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...                                              
fastJT.vrb:14: LaTeX Error: Something's wrong--perhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...                                              
fastJT.vrb:14: LaTeX Error: \begin{beamer@framepauses} on input line 177 ended 
by \end{enumerate}.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
tJT.tex:177: LaTeX Error: \begin{beamer@frameslide} on input line 177 ended by 
\end{beamer@framepauses}.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
tJT.tex:177: LaTeX Error: \begin{document} ended by \end{beamer@frameslide}.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...                                              
fastJT.vrb:52:  ==> Fatal error occurred, no output PDF file produced!

--- failed re-building 'fastJT.Rnw'

SUMMARY: processing the following file failed:
  'fastJT.Rnw'

Error: Vignette re-building failed.
Execution halted