Hi, you can make your Openfire server responsible again if you delete the Kraken folder and Kraken.jar under "plugins" folder. After deletion, start your Openfire server again.
To fix the Openfire 3.7.0 crashing with Kraken plugin, update your Kraken plugin to 1.1.3 beta3 release from here.
This has minor problems with Yahoo! gateway, but other than that it works fine. If you want to use the older Kraken plugin, you need to downgrade your Openfire installation to 3.6.4