vpn connection: error 789 immediately

[steph]

hi,

i've got a problem connecting via vpn. the vpn connection was set up on
my notebook by our systems administrator, and is supposed to work - but
it doesn't. i've got windows xp sp2 and i connect to the internet via
adsl. when i start the vpn connection i immediately get error 789
(L2TP) - without any data being transferred over the adsl connection.
I've searched for a solution to this problem some time now - and there
seem to be some topics about IPsec and NAT-T
(http://support.microsoft.com/default.aspx?scid=kb;en-us;818043) -
but it didn't work for me. Maybe it's a ports issue? I'm lost.

Thanks for any input,
stephan

 

[steph]

problem's cause: ipsec-task failed to start. it's obvious, but ...