Problem: some pages could be found by Search, but could not be displayed, as if they did not exist

My version of Mindtouch: Deki MindTouch Core v. 10.0.4
My wiki contains > 1280 pages.

Description: Some pages (for instance www.Christipedia.nl/artikelen/E/Egypte; http://www.Christipedia.nl/artikelen...Hervormde_Kerk) were (are?) existent and could be found by the Search function. They were shown on the list of findings. However, they could not be opened. It was as if they did not exist. For Mindtouch showed the dialogue window in order to let me create a new page. Pages referring to them by a hyperlink show a red link color.
After reconstructing (rebuilding) the search index (an administrators function under 'Cache management'), the pages could no longer be found. They seem to be lost. However, the are not deleted and they are absent in the list of deleted items.

How can I recover those pages?