A picture for relaxation:
It is probably a fresh bug there as it seems to be happening far more frequently with version 2008 (with ot without SP1) as compared to 2005. Luckily it has no effect to code being written, the problem clearly relates to debugger. At some point there is a crash, though which the IDE perfectly survives but longer can start a new debugging session until IDE is entirely restarted.
I have met this problem in VS 2008 Team with SP1 too;When I start debug with F5, it popup this dialog and the ide stops working, and I must reboot the IDE;But sometimes debug works normally,so I don’t know what’s happening on;I am googling to find solutions.