As a followup, in case this is of use to others, I got my code working by altering R-2.8.1/src/library/graphics/R/screen.R slightly, removing the sole reference to "mfg", as follows.
assign("par.list", c("xlog","ylog", "adj", "bty", "cex", "col", "crt", "err", "font", "lab", "las", "lty", "lwd", "mar", "mex", ##"mfg", "mgp", "pch", "pty", "smo", "srt", "tck", "usr", "xaxp", "xaxs", "xaxt", "xpd", "yaxp", "yaxs", "yaxt", "fig"), envir=.SSenv) -- View this message in context: http://www.nabble.com/Error-in-par%28split.screens--n--%29-%3A-parameter-%22i%22-in-%22mfg%22-is-out-of-range-tp22873439p22878253.html Sent from the R devel mailing list archive at Nabble.com. ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel