Rewrote most of the function to conform more closely to RFC 822. It also is used to separate the username from the domain. We don't want to allow special characters in the address. The square brackets are required. Basically, a word is either an atom or quoted string.
Domain is symbolic name.
Check if it's valid. Make sure there's a host name preceding the domain. Try reloading the page then use the 'email a script' feature again. Please check your address then submit again. Remove the character and submit again.