This has nothing to do with the wp version. Analytics360 simply stopped working on 19 Sept 2012!
Worse: I've tried to tell the developers, applied for their Google group, am still not even 'accepted'!
I've told Mailchimp directly and they continually say they've told the developer, but the developer seems to be on hibernation?
Note: The traffic data shows zero (although our high traffic is still there), while the subscriber numbers ARE being updated. Very weird. A bug.
Strangely, it had always been working before (for 3 months!).
Just stopped 19 Sept. for no apparent reason.