How can I re-activate a member's subscription after PayPal silent post fails?

My client has a member on her site ( whose subscription lapsed because of a 500 error during PayPal silent post after successful re-upping. Now I can't change that subscription's status from 'Expired' to 'Active' in that member's subscription details screen.

The key seems to be...
*) Subscription Dates and Status are validated when saved and might result in a different value then the one specified above.

...a footnote just above the 'Save Changes' button -- but how do I get the member's subscription to properly validate again? To clarify, the recurring payment DID happen on PayPal, that success just wasn't conveyed back to

Thanks for your assistance.