Meta bug for all types of cross-references, like cross-references to headings, tables, illustrations or text.
Created attachment 141749 [details] Screen dumps leading into error
Created attachment 141750 [details] Screen 2
Created attachment 141751 [details] Screen 3
OK, this is weird guys; I had an idea and looked into the database connections for Base. There were some. I deleted all of them and restarted Writer. Now Insert > Cross-reference worked. I re-instituted the Base mysql connection, which is on a local Ubuntu Server. Tried Insert > Cross-reference again and it failed as previously described. As I said, weird. And my head is too old and tired to even think about it. So it seems if I want to use Insert > Cross-reference I better not have any Base data connections configured. Over to you... love to hear your thoughts.