Note: if logging in to Scenario Navigator for the first time fails then make sure that you tried the following:
1) In the login screen click on the "change server" button
2) Change the server to SQL express 2005
3) Select the server from the drop down box
4) Enter the default username and passowrd combination respectively "sa" and "scenarionavigator"
5) Close the "change server" dialog window and login.