Strange... I could not log in to Admin Console even after your suggestions.
I'm using WAMP on localhost so I did this:
1) Opened "openfire" database in PHPMyAdmin
2) Opened "ofuser" table
3) Found (at install time generated user) "admin"
4) Edited cell in column (at install time created) "plainPassword"
4a) New password was entered
5) Login was successfull [username: admin / password: see 4a)]
Please do file a bug-report on this one.
Since I'm running on localhost I do not have any certificates installed that should break the functionallity - or?