I tested it by the data which you sent, but there was not the problem.

Because demo10.joomler.net was Joomla!1.0.15 of the English version, I posted there.

username:guest
password:guest

Please watch Blog menu after login.

Thank you!

ps.
When I getted this article, the same problem happened.
But I was recovered when I posted the same article again.

I do not understand it at all.

In the solution of this problem, I hit on only a method posting again now.

Please give me time for a while.