Error(s) in re-building vignettes:
  ...
--- re-building ‘mlergm_tutorial.Rmd’ using rmarkdown
Loading required package: ergm
Loading required package: network
network: Classes for Relational Data
Version 1.14-377 created on 2019-03-04.
copyright (c) 2005, Carter T. Butts, University of California-Irvine
                    Mark S. Handcock, University of California -- Los Angeles
                    David R. Hunter, Penn State University
                    Martina Morris, University of Washington
                    Skye Bender-deMoll, University of Washington
 For citation information, type citation("network").
 Type help("network-package") to get started.


ergm: version 3.9.4, created on 2018-08-15
Copyright (c) 2018, Mark S. Handcock, University of California -- Los Angeles
                    David R. Hunter, Penn State University
                    Carter T. Butts, University of California -- Irvine
                    Steven M. Goodreau, University of Washington
                    Pavel N. Krivitsky, University of Wollongong
                    Martina Morris, University of Washington
                    with contributions from
                    Li Wang
                    Kirk Li, University of Washington
                    Skye Bender-deMoll, University of Washington
Based on "statnet" project software (statnet.org).
For license and citation information see statnet.org/attribution
or type citation("ergm").

NOTE: Versions before 3.6.1 had a bug in the implementation of the
bd() constriant which distorted the sampled distribution somewhat.
In addition, Sampson's Monks datasets had mislabeled vertices. See
the NEWS and the documentation for more details.

Quitting from lines 132-133 (mlergm_tutorial.Rmd) 
Error: processing vignette 'mlergm_tutorial.Rmd' failed with diagnostics:
VECTOR_ELT() can only be applied to a 'list', not a 'double'
--- failed re-building ‘mlergm_tutorial.Rmd’

SUMMARY: processing the following file failed:
  ‘mlergm_tutorial.Rmd’

Error: Vignette re-building failed.
Execution halted