[FIXED] After a while of agonizing I solved this by uninstalling all my GWT related plugins from Eclipse... I discovered that they were for some reason for an older version of eclipse to the one I have. I installed the latest GWT plugins, manually downloaded the latest GWT SDK and linked it to my projects build path and now the project is compiling. Somewhere along that process was the solution 
I'm trying to deploy a web version of my game, which works fine on desktop and when exporting to a JAR, but for the life of me I cannot get it to pass through GWT.
As far as I can tell I've followed the normal process for creating the web app; Right click the gwt project folder in Eclipse -> Google -> GWT Compile. But when I click on it nothing happens. I get no popup, console feed and nothing changes in the WAR directory.
Can anyone suggest what I might be missing? Or an alternate way I can export my game as a web app?