The most likely cause is that the destination file name contains an invalid character.
At least this is the only way I can get this error.

E.g.

import shutil<br></br><br></br>shutil.copyfile("I:/Temp/ro/test.txt", "I:/Temp/ro/test*1.txt")

On a Mac (or any *nix system) you'd get away with this, but not on Windows.