Could not load file or assembly 'System.Core, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e, Retargetable=Yes' or one of its dependencies. The given assembly name or codebase was invalid. (Exception from HRESULT: 0x80131047)

我在Google上了解到，出现这个错误是因为Orchard引用Autofac 3.0，而使用Autofac 3.0可能会出现这个问题。遇到这个错误，你需要给机子打上KB2468871这个补丁即可解决问题。