I am unable to edit the Start and Expiry Dates in User Subscriptions.

Whenever I update the dates, and hit Update or Save, the fields get filled with zeroes and database doesn't get updated.

I have the same problem, same symptoms, only using MySQL5.  Providing you with FTP access is not a solution, since we are developing the site offline on a non-Internet-connected server.  (Will not post to live server until it works<g>.) So please post details if you find a substantive solution!

Also interesting is that my testing shows that I *can* successfully update the "Access Limit" field, so it is not that the data update is not happening... it is just losing the Start Date and Expire Date values.  It sure seems like a problem with the SQL or date formats, etc, but Joomla! debug does not seem to capture the JCS MySQL commands for adding or updating a subscription, so I am stuck unless I set up a full debug session (and my Zend Studio is broken.  ).

Thanks,
  -t