title: Error accessing uncompiled pages using ISA Server 2006 SP1
body: <p>We are in the processing of configuring a portal to use ISA Server as our front end security provider.<br>
  So we are using ISA Server 2006 SP1.</p>
  
  <p>Unfortunately when we access .net applications through ISA Server, the first time they are accessed.<br>
  i.e. They are not compiled yet, the following  error appears:<br>
  Error Code: 500 Internal Server Error. The parameter is incorrect. (87)</p>
  
  <p>In the ISA Monitoring logs, this shows:  </p>
  
  <blockquote>
    <p>Failed Connection Attempt<br>
    Log type: Web Proxy (Reverse)<br>
    Status: 87 The parameter is incorrect.   </p>
  </blockquote>
  
  <p>Once the application is compiled, the error never appears.<br>
  Does anyone know how to resolve this, so the site works correctly the first time?</p>
  
  <p>Some additional information:  </p>
  
  <ul>
  <li>The websites accessed are running on windows server 2008 64 bit - standard edition, and occurs for Sharepoint as well as standard .net websites.</li>
  <li>ISA Server is running on Windows server 2003 R2 SP2 Standard eidtion</li>
  <li>The firewall on the windows server 2008 box allows all access. (To rule this out.)</li>
  <li>Nothing odd appears in the IIS logs or firewall logs.</li>
  </ul>