Problem with Eclipse/Jetty in Tapestry 5 Tutorial

I'm wor开发者_C百科king through this Tapestry 5 tutorial and I'm stuck on the "Running the Application inside Eclipse" step.

When I go to the Eclipse run configurations, select Jetty Webapp, then click New, I get the following error:

An error has occurred. See error log for more details.

Path for project must have only one segment.

Any suggestions on this one? I'm not new to web development, but I am new to Eclipse and Tapestry.

I'm not exactly sure why, but after I ran Project > Clean... I could then add the run configuration just fine.