Infoobjects greyed out

Hi,

I am trying to install business content infoobjects in the development system. As soon as I collected the necessary objects into the right side window most of them became greyed. Can someone tell me why is happeneing. They were green before I dragged to the right side window. If I go ahead and install them, It will say some objects are missing business content can't be installed. I appreciate your thoughtful responses.

Thanks,

Rao.