You may have already heard of an issue with the August CU for WSS and potentially problems when re-attaching content databases after application of this cumulative update. It is documented on Stefan Goßner’s blog at http://blogs.technet.com/stefan_gossner/archive/2009/09/14/important-be-careful-when-installing-wss-august-cumulative-update.aspx?CommentPosted=true#commentmessage