Error(s) in re-building vignettes:
--- re-building 'FuzzyNumbersTutorial.Rnw' using knitr
Loading required package: knitr
Warning in system(paste(shQuote(texi2dvi), if (quiet) "--quiet" else "",  :
  running command '"C:\PROGRA~1\MiKTeX\miktex\bin\x64\texify.exe" --quiet --pdf "FuzzyNumbersTutorial.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 'FuzzyNumbersTutorial.Rnw' failed with diagnostics:
running 'texi2dvi' on 'FuzzyNumbersTutorial.tex' failed

LaTeX errors:
bers/vignettes/FuzzyNumbersTutorial.tex:1088: Package xcolor Error: Undefined c
olor `fgcolor'.

See the xcolor package documentation for explanation.
Type  H <return>  for immediate help.
bers/vignettes/FuzzyNumbersTutorial.tex:1550: LaTeX Error: Command \end{center}
 invalid in math mode.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
bers/vignettes/FuzzyNumbersTutorial.tex:1550: LaTeX Error: Something's wrong--p
erhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
bers/vignettes/FuzzyNumbersTutorial.tex:1550: LaTeX Error: Something's wrong--p
erhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
bers/vignettes/FuzzyNumbersTutorial.tex:1583: LaTeX Error: Command \end{center}
 invalid in math mode.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
bers/vignettes/FuzzyNumbersTutorial.tex:1583: LaTeX Error: Something's wrong--p
erhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
bers/vignettes/FuzzyNumbersTutorial.tex:1583: LaTeX Error: Something's wrong--p
erhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
bers/vignettes/FuzzyNumbersTutorial.tex:1641: LaTeX Error: Command \end{center}
 invalid in math mode.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
bers/vignettes/FuzzyNumbersTutorial.tex:1641: LaTeX Error: Something's wrong--p
erhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
bers/vignettes/FuzzyNumbersTutorial.tex:1641: LaTeX Error: Something's wrong--p
erhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
bers/vignettes/FuzzyNumbersTutorial.tex:1664: LaTeX Error: Command \end{center}
 invalid in math mode.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
bers/vignettes/FuzzyNumbersTutorial.tex:1664: LaTeX Error: Something's wrong--p
erhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
bers/vignettes/FuzzyNumbersTutorial.tex:1664: LaTeX Error: Something's wrong--p
erhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.

--- failed re-building 'FuzzyNumbersTutorial.Rnw'

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

Error: Vignette re-building failed.
Execution halted