Doh!
I'd put 'php?id=' instead of 'php?event_id='. What an idiot.
I still have the error message at the bottom of the page, though. Can I just delete the mysql_free_result php block to make the error go away, or will that cause problems?
Am also getting a character encoding glitch, with the £ sign and apostrophes being represented by the � symbol.
You can see the effect by clicking the 'more . . . ' link in the 'Quick Links' area HERE
If anyone has any ideas about the encoding or the 'mysql_free_results' glitches, I'd appreciate your thoughts.