Cause

On a page in the project, no value has been entered for the property selected in the Number of pages / page name per property setting.

Solution

1. In the Message management dialog, double click on the message to locate the relevant page in the tree view in the page navigator.
2. Use the popup menu to open the Page properties dialog and enter a value for the property named in the message text, which you selected in the settings for the pages (under Settings > Projects > "Project name" > Management > Pages > Number of pages / page name per property).
3. Select Page > Number of pages / page name per property.
4. Then start a new check run.