Windows Workflow can be a bit of a pain to debug some days. In particular there are often scenarios where an exception gets swallowed somehwere in the runtime and you go off and spend 20 hours barking up the wrong tree.

Someone had one of these issues using some of the sample code from one of my MSDN articles today.

http://forums.microsoft.com/MSDN/AddPost.aspx?PostID=575571&SiteID=1&ReturnUrl=

A hot tip is to turn on some of the debug tracing in the runtime- easy to do. Just bigg the following into your config file.

<system.diagnostics>
    <switches>
      <add name="WorkflowTraceToDefault" value="1" />
      <add name="Host" value="All" />
      <add name="Runtime" value="All" />     
      <add name="Activity" value="All" />
    </switches>
  </system.diagnostics>