problems with posting to forms with twill

[garnet2k]

hi
i use python with twill/mechanize to post some texts to my web sites.
strangely it works sometimes and sometimes not.
i use
twill browser to go to the page with the form, then post the texts and 'press' post button. the fields and button are correct.
something like:

>>> t.fv('2', 'message', 'ffgh')
>>> t.submit('post')
Note: submit is using submit button: name="post", value="postit"

if i only see this, the message isnt there.
but sometimes i see:

>>> t.fv('2', 'message', 'ffgh')
>>> t.submit('post')
Note: submit is using submit button: name="post", value="Изпрати"

Following HTTP-EQUIV=REFRESH to http://www.magicaura.com/new_magicaura.com/web/root/forum/viewtopic.php?f=2&t=5743&p=70003#p70003
>>>

and the message is there.
what it the problem?