Bob,
This could be many items. Normally the Outlook troubleshooter could get us started but that isn't the case in your situation.
rc.crm.dynamics.com/.../outlook-troubleshooting.aspx
I don't know what you have tried so here are a list of items I would do:
1. Delete the current setup and redo the connection.
2. Delete the current setup and then open Outlook and turn off all the add-ins. and then re-enter the configuration information.
3. Run a repair on the Outlook CRM Client.
4. Apply the latest update - UR 13 to the client.
5. Call Microsoft Support - this will be a n/c support incident since you are using CRM Online.