Conference Room List Slow To Load or Doesn't Load at All

Openfire 3.7.1 with MySQL

After Openfire has been running for 5 days or so, when our users browse Conference Rooms in Spark (e.g. Actions > Join conference room), the list either takes more than a minute to load, or it doesn’t load at all. Also, if the “Show conference service in tab” preference is set, it does not display next to the Contact tab as expected. Bookmarked conference rooms don’t seem to be affected. Once Openfire has been restarted, everything works fine – the conference room list loads in a matter of seconds, and the Conference tab is displayed. A debug log has been attached to this message. Please let me know what I can do to sort this out.
debug.log.zip (61728 Bytes)

Any ideas? Anyone? Is it possible to restart the conferencing subsystem without restarting the entire openfire service?