Error(s) in re-building vignettes:
  ...
--- re-building ‘otsad.Rnw’ using knitr
Error: processing vignette 'otsad.Rnw' failed with diagnostics:
Running 'texi2dvi' on 'otsad.tex' failed.
LaTeX errors:
! Undefined control sequence.
l.239 \hlkwd{install.packages}\hldef
                                    {(}\hlsng{"devtools"}\hldef{)}
? 
! Emergency stop.
! Emergency stop.
l.239 
      
End of file on the terminal!

!  ==> Fatal error occurred, no output PDF file produced!
--- failed re-building ‘otsad.Rnw’

SUMMARY: processing the following file failed:
  ‘otsad.Rnw’

Error: Vignette re-building failed.
Execution halted