title: Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData) returns String.Empty
body: <p>i have an asp.net mvc3 application. Now i want to save userdata in</p>
  
  <blockquote>
    <p>C:\Users{AppPoolUserAccount}\AppData\Roaming\MyProgramm...</p>
  </blockquote>
  
  <p>On first call of <code>Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData)</code> i only get "" (String.Empty). 
  On second call <code>Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData)</code> returns correct path...</p>
  
  <p>Note:
  The routine is in a Login-Context. I want to save username and sessionID in a xml-file
  to prevent that two users are logged in simultaneously via one user-account.</p>
  
  <p>Why?</p>