What are the contents of your ear file? For a simple hello world EJB, all you need are:
and the only thing you need in the jar file is the hello world class.
If this does not help, please post the source code for your web service. Enclose the source code within 'code' tags. You can do this by selecting the source code and then clicking the Code button. Also use the Preview button to ensure proper formatting before submitting.