<p>Getting sporadic errors from users of a CMS; Ajax requests sometimes result in a "501 Method not implemented" response from the server. Not all the time; usually works. </p>

<p>Application has been stable for months. Users seem to be getting it with Firefox 3. I've seen a couple references via Google to such problems being related to having "charset=UTF-8" in the Content-type header, but these may be spurious</p>

<p>Has anyone seen this error or have any ideas about what the cause could be?</p>

<p>Thanks</p>

<p>Ian</p>

You may want to check the logs of the server to see what's causing the issue. For example, it might be that these requests are garbled, say, because of a flaw in the HTTP 1.1 persistent connection implementation.