I had the WP app installed on my iPhone 1st gen 2.0 firmware and everything worked fine on both mine and my associates websites on different domains. Last night I upgraded to 2.0.1 and have been getting the same xmlrpc error for both domains. Later tonight or tomorrow I’m going to try to restore the phone back to 2.0 and see if that resolves the issue for me, all other advice and help/FAQ’s I’ve read haven’t resolved it, and the phone’s firmware the only thing that has changed. We are using WP 2.6 on both domains.