Error(s) in re-building vignettes:
--- re-building ‘constraints.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Loading required package: OpenMx
OpenMx may run faster if it is compiled to take advantage of multiple cores.
Quitting from lines 109-110 (constraints.Rmd) 
Error: processing vignette 'constraints.Rmd' failed with diagnostics:
replacement has length zero
--- failed re-building ‘constraints.Rmd’

--- re-building ‘forests.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
--- finished re-building ‘forests.Rmd’

--- re-building ‘getting-started.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Quitting from lines 110-111 (getting-started.Rmd) 
Error: processing vignette 'getting-started.Rmd' failed with diagnostics:
replacement has length zero
--- failed re-building ‘getting-started.Rmd’

--- re-building ‘score-based-tests.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Quitting from lines 80-81 (score-based-tests.Rmd) 
Error: processing vignette 'score-based-tests.Rmd' failed with diagnostics:
replacement has length zero
--- failed re-building ‘score-based-tests.Rmd’

--- re-building ‘semforest-focus.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Quitting from lines 66-72 (semforest-focus.Rmd) 
Error: processing vignette 'semforest-focus.Rmd' failed with diagnostics:
polygon edge not found
--- failed re-building ‘semforest-focus.Rmd’

SUMMARY: processing the following files failed:
  ‘constraints.Rmd’ ‘getting-started.Rmd’ ‘score-based-tests.Rmd’
  ‘semforest-focus.Rmd’

Error: Vignette re-building failed.
Execution halted