The site always sends out an activation mail as long as the user fills in the required fields correctly.
First thing you'd want to check is so the email doesn't block the mail and delete it, or the simple fact that it gets placed in the junk folder of the mail. If you are unable to know this or locate any activation mail it could be the email provider itself that doesn't work well.
Create a new account in that case but use another kind of mail like hotmail for example.
