NoClassDef error with restlet/gwt

So it's been awhile since I've done any java coding and I'm a little rusty. I'm missing the hand holding that .NET does for you in terms of configuration.

So I'm making a GWT app in Eclipse (deployed on App Engine) and I'm trying to use the Restlet framework to avoid using RPC (I want to be able to have iOS etc clients access the same server service). I'm getting a NoClassDefFoundE开发者_开发技巧rror at run-time for the ClientProxy class (part of the restlet core API jar). Now I've got the jar in the WEB-INF/lib folder and I configured my build path so it's there (is there a difference between adding a file as a JAR and an External JAR?). Everything compiles nicely so I know it's there but then poof, it can't find the class file at run time.

What am I overlooking here, I'm sure it's obvious.

You need to use the GAE-friendly version of Restlet: http://wiki.restlet.org/docs_2.0/13-restlet/275-restlet/252-restlet.html