Error(s) in re-building vignettes:
--- re-building 'ggwordcloud.Rmd' using rmarkdown
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=12, height=16' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=16, height=16' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=12, height=16' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=12, height=16' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=8, height=16' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=12, height=12' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=16, height=12' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=16, height=12' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=12, height=12' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=12, height=16' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=12, height=12' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=8, height=12' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=8, height=12' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=12, height=16' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=12, height=16' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=8, height=12' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=8, height=12' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=8, height=12' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=12, height=12' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=12, height=12' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=8, height=12' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=12, height=12' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=8, height=12' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=8, height=8' are unlikely values in pixels
Warning in png(filename = tmp_file, width = gw_pix, height = gh_pix, res = dev_dpi,  :
  'width=8, height=12' are unlikely values in pixels
Warning in wordcloud_boxes(data_points = points_valid_first, boxes = boxes,  :
  Some words could not fit on page. They have been placed at their original positions.
Some words could not fit on page. They have been removed.
Quitting from lines 170-173 (ggwordcloud.Rmd) 
Error: processing vignette 'ggwordcloud.Rmd' failed with diagnostics:
package or namespace load failed for 'dplyr' in library.dynam(lib, package, package.lib):
 DLL 'dplyr' not found: maybe not installed for this architecture?
--- failed re-building 'ggwordcloud.Rmd'

SUMMARY: processing the following file failed:
  'ggwordcloud.Rmd'

Error: Vignette re-building failed.
Execution halted