Having set up Mnet, while those users who've been given roaming capability can see the link in the Network servers block, the Moodle admin instead gets the error message atttached. In order for admin to have the link to the remote site they need to be given the roaming user role. Yet they automatically have the capability to roam to a remote site so this shouldn't have to be done? See forum thread here http://moodle.org/mod/forum/discuss.php?d=167030#p733378