I set up a friend to use Contribute CS4. He is set up as the Publisher. When I send him the connection key, he gets the note that comes with it but not the email attachment with the "key." I have done this before (although not with this version) and haven't had a problem. Any help would be much appreciated!
What email client is he using? Is it rejecting the stc file?
You can always try to save the file to your local machine, then send it in an email as an attachment to see if the problem is with Contribute or with his email settings.