Closing the project that is on Project Server
For those of you that are using Project Server 2007, this post should be interesting. There is an issue in Project Professional 2007 that sometime manifests itself when you close a project, which is on Project Server 2007, using the X button in the top right corner of the window. As the result you will be locked out of that project.
To avoid this problem you should use the File->Close menu ( as recommended by Jack Dahlgren).