From NT 4 + cygwin, rsync does not seem to resolve the euro symbol correctly for filenames, thus it fails to copy that file. From XP + (cygwin or interix, never triex interix with NT4), the euro symbol shows as a question mark, the files do get copied. Am i posting this to right place?
Rsync doesn't care about special characters other than '/' and a terminating null (and, in some instances, a newline). The character showing up as a question mark is either a font problem or a character-set problem -- rsync just uses the characters as it finds them. For instance, copy the file back to XP (to a new location) and you should see the original euro symbol. See also the fname-convert patch in the patches directory for a patch that adds a way to use iconv to perform character-set translations.