[R] sourced plot commands not working

[SHANE MILLER, BLOOMBERG/ 731 LEXIN]

I have source a script running with no errors that ends in these lines:
==============
for (i in 2:3) win.graph()
dev.set(2)
levelplot(avg ~ procs * size, rrt, drape=T, colorkey=T,main="ops/sec",scales=list(x=list(tick.number=15),y=list(log=10)))
dev.set(3)
levelplot(avg ~ procs * size, ort, drape=T, colorkey=T,main="ops/sec",scales=list(x=list(tick.number=15),y=list(log=10)))
=============
The graphics devices windows appear, however, there is no graph
and the background of each window is gray indicating no active
graph.

However, if I copy and paste these commands from the script and
enter them into the console, they run fine. why?

R 2.8.1 2008-12-22 on windows.