First of all, was there enough space on the drive for a 500 mb file? Second of all, does it run flawlessly with smaller files? Are you using the latest version of Samba?

Samba really wasn't meant to handle such large files. I have done it every so often, but it really is a heavy load and taxes the system. If you're going to regularly copy such large files over the network, I highly, highly suggest you consider setting up an FTP server on the linux machine.

This is not to say that it shouldn't work, because it should. How fast is the Mandrake machine? (processor and ram) In addition, I just want to make sure: smaller files DO copy over flawlessly, right?