Message notification email contains broken link to message

Hi,

I have the message system enabled on jobs and experts.

When a message is sent via the inbox > compose feature the email triggered has a broken link...

"[username shows here] has sent you a message on [site name shows here]

[message shows here]

Check your messages here /demo/wp-admin/admin-ajax.php?message_id=451 "

(In this URL partial URL example demo is the name of the multisite this has come from.)

This was triggered by sending a message between users on http://twid.simplecsr.com/demo/

Thanks
chris