I experiment to toggle some fields in firefox' http request, and find that it's the Accept-Language field which break ipp down. Further dig into scheduler/client.c make it clear that cups do not treat Accept-Language field completely, it just take the first candidate from the priority list. So if your highest priority language is broken or absent in cupsys, your http request may fail in some condition.
The work around include use en (or any other working language in cupsys) as your highest priority language, or modify scheduler/client.c yousrself to make it stick to a working language. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]