Redmine

Have you tried googling it? This search yields some results you should try, but from what I read it's most probably a problem with Ubuntu and/or ActionMailer.

Let me quote myself:
I red all the guides and helps I could find with google but nothin seemed to help

Really i did. i tried everything, maybe it just does not work with debian.
I had problems with installing gem etc too, because "gem update --system" was not allowed and the sources where just outdated .. (got 1.2.0 but needed 1.3.7 or something)
Even sendmail does not work.

I can't edit i'm sorry for doublepost.
I just restarted the root and started everything again and it worked.. I don't know what the reason for this was but now it works.

Sendmail in the email.yml or sendmail on the command line does not work? Can you ping or resolve the ip (either with host or dig) of the host you are trying to send the mails to from the host with redmine on it? Can you telnet the SMTP port from there?

Anyway, it looks to me as if you are trying to mix apt-installed and gem-installed gems, right? That's generally a bad idea, either install up to ruby from apt, rubgems by hand and everything from there with gem, or stick with apt and get the redmine package from apt.

Oh, I had to take care of something else in between writing my answer, happy to hear that it works :-)