I've tried that and the base page did not have this error.
But the example page uses a very basic editor, so I gradually added some configuration options that I use in my own test page.
That's how I found out that the error occurs when I set: CustomCulture="nl-NL"
The current code which produces the error is:
<
CE:Editor ID="Editor1" CustomCulture="nl-NL" AutoConfigure="Simple" Height="200" runat="server"></CE:Editor>
Regards, Marja