I think you are right when you said
Max Rydahl Andersen escribió:
something in your project/workspace is not consistent
Doing Project->Clean with project that has been created with another eclipse and jboss version, the npe is thrown, but if I create a new project (ear with ejb-project and web-project) the error not occurs.
The project that have this error was created with eclipse 3.6.1 and JBossAS Tools 2.2.0.v20110729-2066-H221-Final and seems that when the project is opened on worksapce with eclipse 3.6.2 eclipse-jee-helios-SR2-win32-x86_64 and jbosstools-3.2.1.Final.aggregate-Update-2011-08-01_12-53-33-H1305) have the npe when project-->clean is executed.
With eclipse wtp just installed, don't have this error.