Publishing Web Module in Eclipse Luna

I have come across an error when trying to deploy a webmodule to a tomcat server in Eclipse Luna. The error message is not very helpful. And i would like some help in tracking down the cause. The error i get is

Could not publish to the server.
org.eclipse.wst.common.componentcore.internal.flat.flatfile cannot be cast to      org.eclipse.wst.common.componentcore.internal.flat.IFlatFolder.

Any suggestions on how to interpret the message would be nice. I have tried in various ways to edit the web deployment assembly.

The only other thread covering this issue is this one, that did not get an answer

http://ift.tt/1JkWsiM