Drat, the first db update to the plugin in a month. Update is in the SVN and the package is updated too, but I haven't worked out the details on safely doing db updates via Mura yet so the table has to be updated manually for now:

ALTER TABLE mf_forum ADD COLUMN `lastPostID` CHAR(35) AFTER `filename`;

Adjustments might be required if you have added a prefix to the table.

FYI, it deals with a performance issue; an index on an "order by" in MySQL is ignored and this results in a huge performance hit.