Getting Error "'OpportunityProjectItems__r' is not a valid child relationship name for entity Project " on visual force page while clicking project to open. Can you suggest how to resolve this?

This is happening only for one profile

Getting Error "'OpportunityProjectItems__r' is not a valid child relationship name for entity Project " on visual force page while clicking project to open. Can you suggest how to resolve this?

This is happening only for one profile

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What does this error mean.It is a visuval force error it is happned after package the application.In unmanaged code it is working fine .