Start with rebooting the server to make sure that there isn't any locks being held by the operating system.  

Beyond that, I would strongly suggest that you contact support directly about upgrading to a current version. I know that there have been numerous revisions to the back end architecture of the application itself as well as updates to the server engine that resolved a lot of locking issues.  That alone might resolve the issue for you, and at a minimum gets you up to a version that we can provide support for.