delivery error message - iTunes Producer

I have received the following error messages when trying to "Deliver" my .ibooks file through iTunes Producer. I have tried to double click the error messages and can't locate the source of the problem.

1. Apple's web service operation was not successful

2. Unable to authenticate the package: 10000375554.itmsp

3. ERROR ITMS-3000: "Line 30 column 66: element "audience incomplete; expected element "range", "value" or "values" at XPath /package/book/metadata/audience_info/audience"

Thanks for your help.