Error(s) in re-building vignettes:
  ...
--- re-building ‘examples.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) and/or pandoc-citeproc not available. Falling back to R Markdown v1.
Quitting from lines 43-50 (examples.Rmd) 
Error: processing vignette 'examples.Rmd' failed with diagnostics:
ncol(obj1) is not NULL or ncol(obj2) is not NULL or ncol(obj1) not equal to ncol(obj2)
--- failed re-building ‘examples.Rmd’

--- re-building ‘labels-support.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) and/or pandoc-citeproc not available. Falling back to R Markdown v1.

Use 'expss_output_viewer()' to display tables in the RStudio Viewer.
 To return to the console output, use 'expss_output_default()'.

--- finished re-building ‘labels-support.Rmd’

--- re-building ‘tables-with-labels.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) and/or pandoc-citeproc not available. Falling back to R Markdown v1.

Use 'expss_output_rnotebook()' to display tables inside R Notebooks.
 To return to the console output, use 'expss_output_default()'.

Quitting from lines 61-74 (tables-with-labels.Rmd) 
Error: processing vignette 'tables-with-labels.Rmd' failed with diagnostics:
ncol(obj1) is not NULL or ncol(obj2) is not NULL or ncol(obj1) not equal to ncol(obj2)
--- failed re-building ‘tables-with-labels.Rmd’

--- re-building ‘xlsx-export.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) and/or pandoc-citeproc not available. Falling back to R Markdown v1.
Quitting from lines 20-49 (xlsx-export.Rmd) 
Error: processing vignette 'xlsx-export.Rmd' failed with diagnostics:
ncol(obj1) is not NULL or ncol(obj2) is not NULL or ncol(obj1) not equal to ncol(obj2)
--- failed re-building ‘xlsx-export.Rmd’

SUMMARY: processing the following files failed:
  ‘examples.Rmd’ ‘tables-with-labels.Rmd’ ‘xlsx-export.Rmd’

Error: Vignette re-building failed.
Execution halted