Plot Expression Result

R Version R version 2.7.0 Under development (unstable) (2008-02-11 r44417)
OS unix
Date Thu Nov 27 15:49:30 2008
Call Called from plotFunction()
Directory /home/RQC/R44417/QC
Log Filename grid.locator-log.xml

Format Plots Error
pdf grid.locator-1.pdf It is invalid to combine unit objects with other types
png grid.locator-1.png It is invalid to combine unit objects with other types
ps grid.locator-1.ps It is invalid to combine unit objects with other types