Site usage statistics graph not displayed

I upgraded my site from D5 to D6 and upgraded the Mollom module to 6-x.1.10, and my Site Usage Statistics graph is not visible any more at admin/settings/mollom. My keys are entered properly, and the message that says that the Mollom services are operating correctly is displayed. I am able to log into my account on the Mollom site and view my usage statistics there.

Thanks.