I know this sounds crazy, but have you checked the syntax of the name of the large file you are trying to read? In my past experiences with large fle manipulation, I have only recieved that error when I goof, and actually try to read on a closed file(don't ask, heh) or if the file I'm trying to read from simply doesn't exist(i.e. Typo on the file name). I think that if the data your trying to read from this file was too big, it would give a different error.

Am I making sence?

-- Yes, I am a criminal. My crime is that of defyance.