Error c00ce56e in ie
4 03 2008Quite an interesting problem.
If you set encoding headers for XMLHttpRequests to header('Content-Type' , 'text/html; charset=utf8'); instead of header('Content-Type', 'text/html; charset=UTF-8'); IE7 will give the nice and clear error c00ce56e.
So if you ever get this problem, here's the solution.
update:
Sorry for my brief description of the problem. The problem occurs when setting the charset of a response to a XMLHttpRequest to utf8 instead of UTF-8. IE7 is very strict on naming of the charsets, while Firefox and IE6 (!!!) are a bit more lenient.
I read Microsofts description of the problem at http://support.microsoft.com/kb/304625 where they describe it as "Behavior is by design". 
I’ve run into this aswell actually. I dont even recall it giving any errors, just failing silently.. perhaps it was IE6.
It actually works in IE6! but as I wrote in my update, IE7 is much more strict on naming.