This is an known issue that is being worked on. If you run into this situation close down RootsMagic and then restart it. You will now be able to print your reports.
If you are still experience this issue keep in mind that the focus person for a Modified Register or any other Narrative Descendant report has to have linked descendants. The focus person for any Ancestors Narrative report has to have linked ancestor. Otherwise your report will give the person and your contact info.