title: ClickOnce download fails unless end user has VS2008
body: <p>I'm still working on the problem described <a href="https://stackoverflow.com/questions/760920/clickonce-deployment-error-on-upgraded-net-application">here</a>, trying to get ClickOnce to work from Visual Studio 2008. I originally assumed the problem was related to the fact that the application I was deploying was upgraded from 2005. But that's not the case. I created a new VS2008 application and deployed it with the same result.</p>
  
  <p>I've tried (I think) every possible combination of publish settings (except signing the manifest, which I don't need to do because I'm deploying over an intranet). Most users get the same message.</p>
  
  <p><em>Cannot continue. The application is improperly formatted. Contact the application vendor for assistance.</em></p>
  
  <p>I got another developer who has VS2008 to try opening the application, and it worked for him. Others who haven't upgraded from 2005 get the error message. I'm targeting 3.5, and the 3.5 framework is included in the prerequisites.</p>
  
  <p>The users already have the 3.5 framework installed. I'm wondering if maybe it's installed incompletely or incorrecly. Can anybody think of any other reason users who don't have VS2008 installed wouldn't be able to run a VS2008-generated ClickOnce application?</p>