Hi David,
thanks for your kind reply.
In the meantime I have changed my settings of JEvents, so that the problem does not appear.
When you enable the "Utilize Icos for Navigation" parameter in the Jevents configuration, then you will get a pulldown menu in the frontend, where you can select a certain month/year.
Once you choose any month from this list, it will jump to a link called
www.diabetes-kids.de/jahr/1-mmmmmmmm-yyyyyyyy, which is December 1999.
As I said, I disabled this menu, so you can not see the problem anymore at the frontend.
You can find the calendar at
www.diabetes-kids.de/termine
Best regards and have a nice weekend
Michael