In Live Meeting's
User Accounts window make sure you just have your SIP address in the Sign-In Name field (like
user@domain.com) and make sure the Live Meeting Service URL is empty. LM will use Automatic Configuration to locate the OCS Front-End or Edge server depending on the location of the computer. If you aren't using Automatic Configuration for your OC clients then click the Advanced button to make sure that your OC client settings appear.
But basically there is no URL that you use for OCS, that is simply for connecting to Microsoft's hosted Live Meeting service, so delete the value in that field and try Test Connection without.
Jeff Schertz, PointBridge | MVP | MCITP: Enterprise Messaging | MCTS: OCS