I downloaded the latest editor and all of the samples work in IE7 but not IE6.
I tried browsing this very screen where I am entering this text, because it has your editor on it, but this site won't let me see this screen in IE6 and prompts me to upgrade.
We wish to purchase this and it looks really good, lots of features, very configurable and so on but a client requirement insists it is IE6 compatible and the samples that come with the editor don't load the editor.
CKEditor 4 is not compatible
CKEditor 4 is not compatible with IE 6, you must use the previous version : CKEditor 3.6.6 (after all you're using a browser that it's over 10 years old, so it isn't strange that you must use also older version of other software)