Do you continue to have this issue every time you do svn update?
Do you get the same problem on a clean checkout in a different folder?
I debug using IIS and to do that I set the project properties to use IIS instead of the VS Web server. I always try to remember to set it back to VS Web Server before I merge my changes to svn trunk but occasionally I have forgotten and perhaps if you checked it out on the day that happened it would cause this issue, but in that case it should be fixed by svn update because it is not configured for IIS currently in svn trunk.
I'm working everyday in this visual studio solution using the same platform, Win 7 64 bit and I do not get this error. Do you have SP1 installed for VS 2008?