Vista - Error 8000401a - Windows Live Messenger 2009 (14.0.8050.1202)

Hi all,
can you help me with the last build of WLM 2009 (14.0.8050.1202)?
After installation, when I try to login Live Messenger shows me the error 8000401a "Signing in to Windows Live Messenger failed because the service is temporarily unavailable. Please try again later."
I'm using Windows XP Professional, I don't have any firewall and my Antivirus is Eset NOD32; I have a wireless connection and WLM 2009 works fine on another pc connected to the same router.
I 've done everything, I renstalled it, repaired it, I cleaned registry and I tried logging in with 3 different accounts. I've also deleted "Windows Live Contacts" and "Messenger Cache" folders: I still get that error.

Can you help me with this problem? I would really appreciate it.

Regards

Ugo S.

I found a solution, read this post: point n.2 worked for me

I'm getting the same problem.
I have full access to the internet (everything else is working)
Before installing this update messenger worked every time with no problems.
I don't believe this problem is with my PC. Its a messenger problem.

There are lots of people having this problem and yet we still have no fix.

Get your finger out MS