Once you create the BOMapper project, you have to "link" it to the Visual Studio project.  The project that displays within the BOMapper's treeview is actually the VS project, not the BOMapper project.  So, right-click the project in the treeview and select "Configure", then in the new dialog, select the project that you just created, and click "Select" down in the lower right-hand corner.  That will link the BOMapper project to the VS project and get rid of the red-x for you.

Let me know if you run into anything else

I'm trying to go through the tutorial for Creating a WinForms App since I just downloaded the trial and want to see how things work.  I'm getting to the point where I add a Business Object, then open up the Business Object Mapper to configure it.  I add a new project, point it to my database with a connection string like this: Server=myserver;Database=mydb;User ID=sa;Password=mypwd;Integrated Security=False;  I also tried browsing to the database and having it generate the connection string.  In both cases, it seems to create the project fine, but when I get back to the Mapper, there is still a red x on the project name, and I still cannot configure the business object.  Any idea what could be going wrong here?  I'm at a loss as I have followed the tutorial exactly but cannot get past step 5 of "Configuring the Business Object Mapper Project".  Please help!