Upgrading: 'active cluster service name'??

[hjmangalam]

I recently had to upgrade an older installation of zimbra - trying to upgrade zimbra 5.0.5 -> 5.0.12.

I recently upgraded the underlying OS from Ubuntu 6.06 to 8.04 (after back up) and restarted the existing zimbra 505, which worked fine.

Backed up again, and downloaded the new zimbra package and tried to upgrade with the command:

./install.sh --cluster active

but this has immediately sent me into a loop:

Enter the active cluster service name for this node: [hefxxx.psxxx.uxxx.edu]
Please enter a valid cluster service name.
bin data docs install.sh packages readme_binary_en_US.txt README.txt util

the first time, since it seemed to provide a valid hostname in the usual default presentation style [hefxxx.psxxx.uxxx.edu], I hit return, but it didn't take it or anything else resembling this.
Regardless what I put in, this keeps looping, producing the 'ls' output on each iteration.

What is a valid cluster service name and where would I find it? (been looking for over an hour).

TIA
Harry