Thanks for the access codes. I now see the problem. An annoying little mistake (mine, of course). The clue was in the error message: “…./Fanchart.php:1”, meaning the very first line of that file. That is simply:
It should be:
See the difference? I wouldn’t be surprised if you don’t. The second doesn’t have a tiny single space at the start. That is sufficient on some PHP configurations to prevent sending subsequent headers, or making the system think they’ve already been sent once. Hence your issue, but it not showing on my system. It’s a simple error, and one I know well enough to avoid – normally!!
Replacement copy of kiwitrees/library/WT/Controller/Fanchart.php attached.