assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded.

把asp.net程序发布到服务器上，得到错误
this assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded.

很可能是由于.net版本的设置！
你本地开发如果用.net 4.0，但在服务器上却设成了.net 2.0/.net 3.5，就会得到这个错误！
要解决，就把网站放到相应.net版本的应用池内！