Comment not posted: POST required, or missing parameter.
Examples of this error from SupportOffice
http://www.livejournal.com/support/see_request.bml?id=348388
http://www.livejournal.com/support/see_request.bml?id=351139
http://www.livejournal.com/support/see_request.bml?id=351710
http://www.livejournal.com/support/see_request.bml?id=357487
http://www.livejournal.com/support/see_request.bml?id=358162
http://www.livejournal.com/support/see_request.bml?id=360123
http://www.livejournal.com/support/see_request.bml?id=360270
I suggest that the error be added to the FAQ to reduce support requests and provide a specific reference for use in answers.
Current
Some symptoms of this include improper links, buttons that fail to lead to pages on the LiveJournal site, error messages such as "invalid password" or "could not determine journal from arguments", etc.
Draft
Some symptoms of this include improper links and buttons that fail to lead to pages on the LiveJournal site. Common error messages include "invalid password", "could not determine journal from arguments", and "Comment not posted: POST required, or missing parameter."