I would need help with this problem - I have a special web app (web service diagnostic tool), it references web service.

This app dynamically compiles source code, creates assembly and can run it - still OK.
I want write source referencing web service data types - it can load it while compilation process over params, but when method is invoked the file not found is referenced and assembly can not be loaded. Visual studio is trying to load it from app\bin, but this folder doesn't exist.

Thanks for any idea !

Well, since you can't load something that is not there...
Can you separate the projects and ensure the dependent one is compiled last?
...either by using separate projects or a build script that compiles the required pieces first?

Also, if this is already broken into multiple projects, do you have the Project Dependencies checked?