I have a VS 2005 web site that I publish using \"Publish Web Site\", and I clear all the three checkboxes. I also have a deployment project that picks up the published files
Redeployment of the same files also fixed this issue in my case.
So maybe before trying anything else first try to deploy you app again (bin folder content should be enough)
BTW: In my case the error started when C drive run out of space.
Happy coding! ChiTec