Here's your WSE 1.0 tip of the day:

By default, the WSE will give errors that won't give tons of information during errors. During development, you may need to see more explicit error messages, like a stack trace. We use the ASP.NET custom errors settings for this:

<configuration>
<system.web>
<customErrors mode="RemoteOnly" />
</system.web>
</configuration>

You have three options here: On, Off, and RemoteOnly. I recommend RemoteOnly - note that this means you will get the detailed error messages when sending messages from locahost.