title: specflow fails when trying to generate test execution report
body: <p>I've got a project that's using SpecFlow, NUnit and Coypu to do acceptance tests on a web application.  I've got the project building OK via Jenkins on a build server.  Jenkins calls a psake script which runs msbuild on the specs project, then the script calls nunit-console to run the specs/tests, and then I want to generate a report from SpecFlow.</p>
  
  <pre><code>Framework "4.0"
  
  task Default -depends RunSpecs
  
  task BuildSpecs {
      $env:EnableNuGetPackageRestore = "true"
      msbuild /t:Rebuild ReturnsPortal.Specs.csproj
  }
  
  task RunSpecs -depends BuildSpecs {
      exec { &amp; "C:\path\to\NUnit 2.5.9\bin\net-2.0\nunit-console-x86.exe" /labels /out=TestResult.txt /xml=TestResult.xml .\bin\Debug\TheWebApp.Specs.dll }
      exec { &amp; "C:\path\to\SpecFlow\1.8.1\specflow.exe" nunitexecutionreport TheWebApp.Specs.csproj /out:SpecResult.html }
  }
  </code></pre>
  
  <p>That last exec call to specflow.exe fails though, with:</p>
  
  <blockquote>
    <p>The element &lt;ParameterGroup> beneath element &lt;UsingTask> is unrecognized.  C:\Program Files (x86)\Jenkins\jobs\TheWebApp\workspace\Web\Sites\TheWebApp.nuget\nuget.targets</p>
  </blockquote>
  
  <p>A bit of googling hints that maybe it's a problem with the msbuild version being used (e.g. <a href="https://stackoverflow.com/questions/4440665/get-xml-documentation-files-from-tfs-team-build-script">here</a>, <a href="http://social.msdn.microsoft.com/Forums/en-US/dslvsarchx/thread/998002e7-7f06-460a-9ee0-03e1edd419c5/" rel="nofollow noreferrer">here</a>).  But I have <code>Framework "4.0"</code> in my psake script, and the Specs project is targeting .NET Framework 4.0, and it builds fine in the build step, so I'm not sure why specflow seems to be using an earlier version of msbuild.  Or is maybe the problem somewhere else?</p>