Word to the wise - whenever there is an update - DO NOT UPDATE if you intend to play on the Team9K server. Or if you do, make a BACKUP COPY of the origina JAR file first. There is no magic wand to make Bukkit compatible with the new release until they physically modify the code and push the update out which depending on the number of changes, might take anywhere from a few hours to a few days or longer. My suggestion would be to see if you can find a copy of the 1.6.8 JAR file, otherwise you're SOL until Bukkit releases a 1.7 compatible version.