Thanks Ludo and Mauno,
In response to Ludo's question: Last version AFAIK.
It doesn't appear to be a problem strictly with NWiki, though. I created another wiki using the same original Excel file and cutting and pasting it to another wiki, this time using OUWiki and I have the same problem. OUWiki, though, does show a message when you click on 'debug script'. The message is:
"Database problem: Duplicate entry 'garcia' for key 2 (code OUWIKI-ouwiki.php/1613)"
Which I cannot make sense of.
I'm attaching a text file with the HTML code involved.