An error occured while assigning the device to the user. The user is not yet know to the Blackberry agent. It can take several minutes for a newly added user to be fully initialized by the server before they can be provisioned. (16).
Very familiar error...
You may be assigning a handheld to a user from the BlackBerry Manager on a remote computer that is not part of the same Windows domain as the BlackBerry Enterprise Server.
When using Windows authentication, the configuration database does not authenticate the user logging into the workstation. For example, the local computer cannot be authenticated. Because of this, a new account must be created that is capable of authenticating an account on the BlackBerry Enterprise Server against the configuration database.
Try adding a Windows account on the BlackBerry Enterprise Server with the same login name and password as on the remote administratorís computer.
On the Activation issue, try removing the user, wipe the handheld and then re-add user and set a new activation password and do it all over again. For troubleshooting activation, take special note on the stage which it does not respond and refer to RIM's KB-05202 Support - Identifying and troubleshooting enterprise activation issues
, it is a very detail guide.