ProgressIndicator polling error (beta 7)

I get the following error (repeatedly) after removing a ProgressIndicator from the page:

Nov 01, 2012 3:31:38 PM com.vaadin.server.AbstractCommunicationManager handleBurst
WARNING: RPC call to com.vaadin.shared.ui.progressindicator.ProgressIndicatorServerRpc.poll received for connector 161 but no such connector could be found