Did you save the JEvents Config after installing it yet?
Yes, I did that straight away so I was on default settings. I was in a hurry to get something - anything! - up in the new environment.
Since posting the original message, I realised that by using the ical export/import method to get the events into the new system I had actually lost information I didn't want to lose, e.g. original creation times of the events. Although the ical import kept the event date/times as one would expect, the creation times were all set to the time of the import.
I decided to upgrade the old Joomla 1.5 system to JEvents 2.2.9, clear out and reinstall the latest JEvents on the new system, and then let SP Upgrade's extension transfer do the work so I could keep all the original info. H-u-g-e- mistake! Although the Joomla 1.5 upgrade to 2.2.9 went fine and all appeared well, it was quite beyond SP Upgrade to get the stuff across into the freshly reinstalled JEvents on the new system. The JEvents categories weren't transfered and the table vanished from the database. I sorted that out, and finally after several attempts it looked like everything was across but no. Unable to display any events in the front end. It turned out to be because table jev_defaults had mysteriously lost the language and catid columns. I used phpmyadmin to put them back, based on another installation I have, and then, finally, I could display events in the front end. Unfortunately, SP Upgrade has managed to fail to set the 'created by' column in table jevents_vevent so they all have a value of 0 which is displayed as 'Anonymous'. Most annoying because the old v2.2.9 database has all the correct data for that column, so why wasn't it transferred?
Anyway, the bottom line is that after all that messing around I'm still seeing the same error I originally reported.
As regards the horrible upgrade experience, I know you have a script, and I have used it before, but if you look for other posts by me you'll see we had a conversation where I reported a number of problems I had with it. That's why I thought it was a no-brainer to upgrade the old system to 2.2.9 and then use SP Upgrade to transfer to a fresh install on the new system. Wrong! I can see me completely uninstalling JEvents from the new system yet again, reinstalling it anew and trying the script after all.