I'm actually not that familiar with the SEP installation as it was conducted by another department.
What I can tell regarding your questions is:
1. I'm not sure which version exactly is installed, other than it's RU6.
2. The servers hang without BSOD. Weird thing is, they lose communication (no ping, telnet/rclient won't work) but the OS stays on and I was able to log on to one of them, but loading my profile took about 30 minutes. It's like the server was utilizing all its CPU so hard that it took 30 minutes to load.
3. The installation consists of SEP 11 AV, Symantec Live Update, Symantec Management Agent 7.1 and an Altiris task-based handler 7.1. No firewall. Currently it's impossible to uninstall and re-install, but perhaps it will be possible next week.
4. It happened 3 - 4 days after the installation. In a period of 3 days we had 4 such hangs, two of which were on the same server, and two others occured on two other servers (total of 4 hangs on 3 servers in 48 hours).
Alex