After the Application Architect threw an error during a deploy it shut down.  After doing so I received an error attempting to log back in to the Application Architect:

One or more exceptions occurred while firing the topic ‘evt://Projects/ActiveProjectChanged’ (Sage.Platform.Application)

I tried rebooting the server and restarting the SalesLogix services, however, it would still throw the error.  To resolve the problem I had to go into my build directory and delete the contents of the folder.  After doing this I was able to log back in.  The build folder is located, by default, under C:documents and settingsusernameApplication DataSagePlatform.  You can change this path however in the Application Architect so if you have you would need to find that path instead.

On a related note: it is always a good idea to delete the contents of this same folder before logging into a different SalesLogix database.  Like for instance if switching between a development and test system with the Application Architect.