John, the only thing that I can think of is what I mentioned in my last post.....R10 requires the mode to be listed in lowercase, so try changing the "R" in the open statement to "r". Other than that, I'm at a loss......
At the command line you could try this to make sure the file is found:
(findfile "c:\\plinexpt.txt")
If found the path will be returned and that isn't the problem, else it will return nil
