Create an event automatically with Python mechanize

Hello,

I am trying to write a Python script that would create events automatically. I am using mechanize to do that. The strange thing is, when I try to publish my event, I get an error page that I can’t seem to find when I try myself. The page is http://mysite.com/wordpress/wp-admin/post.php?post=501&action=edit&message=10
It’s really strange because my event is in the drafts but was not published and when I try to publish it myself, it does not work.

Thank you for your help,
Ryunos