But when I try to request a tunnel once again it says >There is already a tunnel to '<my-ip>'<... So my question is, what should I do now? :> As I said, there was only a problem with my configuration (icmp blocked on firewall) and it was a reason of tunnel rejection (i improve my configuration and now everything should be ok)...

The tunnel robot only tests tunnels in "requested state" not when they are already rejected. The whole point is that we are not going to send traffic to unsuspecting hosts. As you did not configure your 'firewall' you where not expecting it. If you want a retry you might try and send a good reason to info@sixxs.net why it was down when it was tested the first time and maybe you will get a retry. Honesty is a good thing btw.