AIX problem after moving into a different network

I love the solaris boxes. They are so simple to use!!!

This week I changed the IP Adress wit smitty on our p520 AIX 5.3.

After moving the server into the new network, it started up, but I
couldn't login over the serial console.

There were just message that the NIS server could not be reached.

To get into the "single user mode", I had to insert the DVD with the OS,
jump into the menu on the serial console, select the DVD as boot device
and start from there.

During this run I had to say, that I want a maintenance boot and the
disk to use.

After this, I had a shell, where I could manually modify the files, because
smitty didn't work.

Now the system needs about 3/4 hour to boot fully. Think it was the
automount, which let the system hang, but now I do not have more
time to try, why this is the case.

The system also doesn't boot automatically. Have to boot it from the