I had similar issue and none of suggestion given here worked. I could resolve publishing issue of Protege by using full url instead of http://localhost:8080/essential_viewer/ from browser for essential viewer. It looks like http://localhost:8080/essential_viewer/report?XML=reportXML.xml&XSL=home...

Very first solution: I tried provided solution but it didn't solve the issue. The reason being that in case if you have everything installed correct and working at browser level can still get this error. Means, if your Essential Viewer is perfect in your browser and available at http://localhost:808...