The package was updated to version 0.1-38 on Aug 18th 2016. This is a dependency for the packages 'tm' and 'wordcloud', which are in turn dependancies for PubMedWordcloud.
We can enforce package version by installing from the CRAN archive rather than default.
Lines below can be inserted into the setupINSPIIRED.R script.
slam_url <- "http://cran.r-project.org/src/contrib/Archive/slam/slam_0.1-37.tar.gz"
install.packages(slam_url, repos = NULL, type = "source")