Business Object Export to Crystal Report

[Smithsc]

I've got several business object reports that are shown as Crystal Report format in the infoview. When I try to view these reports all I see is Null in the top left hand corner.
All other reports that export to excel,pdf etc work fine.

Is there something not running which allows me to view crystal report formatted instances and if so, how do I start it up again.

Many thanks

Stuart.