One day ago I installed the messenger/archive agent on one of our NSBS 6

After installation it was possible to log in to the Messenger service for
all our pc's (30 pc's) except for 4 new identical desktops.

We work with a mix of Win98/2000/XP desktops. All the WinXP pc's have
WinXPsp2 installed with the firewall disabled.

The new pc's are our first AMD64 pc's (with WinXPsp2 and firewall
disabled). The rest is all Intel.

Can this be an issue or does it have to be someting else?

The message is: "server is not responding" although I can see at the MA
screen that it is responding to the request.