I don't know if anyone is reading this, but I have more information now.  I
can run the same script on my other computer over and over, change the
height, width and res, and it works every time.  But on the faulty computer,
I can open R, open the script, and run it and it works.  I can re-run it any
number of times and it works.  However, when I change the height, width, or
res settings in the function, I get the error message.  From that point on,
even if I change the height, width, or res back to what worked before, it
will no longer run and I get the error message.  I can only get it to run
again by shutting down the program, re-opening R and the script, and running
it again.  This is just bizarre to me and I have no idea why I am having
this problem.  Thanks if you are still reading, and I welcome any input.
I'm not very technically savvy, but I am running it on Windows XP Pro
Version 2002, Service Pack 3.

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