Office 365 error when try to activate

Nov 19, 2011 at 12:52 PM

When trying to activate in Office 365,

"This solution contains invalid markup or elements that cannot be deployed as part of a sandboxed solution.

file manifest.sml, line 10, character 4: The element 'solution' in namespace 'http://schemas.microsoft.com/sharepoint' has invalid child element 'RootFiles' ...

List of possible elements expected: 'FeatureManifests', 'Activation Dependencies' in ...