Error(s) in re-building vignettes:
  ...
--- re-building ‘basics.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 304-307 (basics.Rmd) 
Error: processing vignette 'basics.Rmd' failed with diagnostics:
need at least two non-NA values to interpolate
--- failed re-building ‘basics.Rmd’

--- re-building ‘classification.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
i Creating pre-processing data to finalize unknown parameter: mtry
x Bootstrap02: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap03: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap04: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap05: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap06: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap07: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap08: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap09: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap10: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap11: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap12: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap13: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap14: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap15: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap16: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap17: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap18: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap19: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap20: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap21: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap22: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap23: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap24: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
x Bootstrap25: preprocessor 1/1, model 1/1 (predictions): Error in approx(lambda, seq(l...
Quitting from lines 156-168 (classification.Rmd) 
Error: processing vignette 'classification.Rmd' failed with diagnostics:
need at least two non-NA values to interpolate
--- failed re-building ‘classification.Rmd’

SUMMARY: processing the following files failed:
  ‘basics.Rmd’ ‘classification.Rmd’

Error: Vignette re-building failed.
Execution halted