Ok, better now. It seems to me that your version of perl was compiled without support for large files. You can verify that by executing "perl -V" from the command line and inspecting the output. You should see something like "-Duselargefiles" and/or "selargefiles=define". If you perl version was compiled without large files support, then you can rebuild it either from source or from .src.rpm (this might be easier, since you are using RedHat).
Also, I would like to draw your attention to this paragraph in the perldoc File::Copy: "An optional third parameter can be used to specify the buffer size used for copying. This is the number of bytes from the first file, that wil be held in memory at any given time, before being written to the second file. The default buffer size depends upon the file, but will generally be the whole file (up to 2Mb), or 1k for file-handles that do not reference files (eg. sockets).". I doubt it will help you now, but it's good to have in mind. :)