Installed it last night, rebooted and ran SL. Got the following error: "unable to find the server domain name. this could be the result of a lost network connection or a server problem. please try again..." blah blah blah.
1. Closed SL and pinged the following: userserver.agni.lindenlab.com and lindenlab.com. Got packets back for both with no problem (faster response than most sites too).
2. Went looking for a debug log of some kind and found the following:
2004-11-19T22:18:36Z INFO Attempting login as: Betty Page
2004-11-19T22:18:36Z INFO Current Directories:
2004-11-19T22:18:36Z INFO CurPath: C:\Program Files\SecondLife
2004-11-19T22:18:36Z INFO AppName: SecondLife
2004-11-19T22:18:36Z INFO ExecutableFilename: newview.exe
2004-11-19T22:18:36Z INFO ExecutableDir: C:\Program Files\SecondLife
2004-11-19T22:18:36Z INFO ExecutablePathAndName: C:\Program Files\SecondLife\newview.exe
2004-11-19T22:18:36Z INFO AppRODataDir: C:\Program Files\SecondLife
2004-11-19T22:18:36Z INFO OSUserDir: C:\Documents and Settings\[USERNAME]\Application Data
2004-11-19T22:18:36Z INFO OSUserAppDir: C:\Documents and Settings\[USERNAME]\Application Data\SecondLife
2004-11-19T22:18:36Z INFO LindenUserDir: C:\Documents and Settings\[USERNAME]\Application Data\SecondLife\Betty_Page
2004-11-19T22:18:36Z INFO TempDir: C:\DOCUME~1\[USERNAME]\LOCALS~1\Temp
2004-11-19T22:18:36Z INFO CAFile: C:\Program Files\SecondLife\app_settings\CA.pem
2004-11-19T22:18:36Z INFO LLControlGroup::loadFromFile unable to open.
2004-11-19T22:18:36Z INFO Loading startup bitmap...
2004-11-19T22:18:36Z WARNING Unable to open file for reading
2004-11-19T22:18:36Z INFO Bitmap load failed
2004-11-19T22:18:36Z INFO Resolving Agni userserver domain name userserver.agni.lindenlab.com
2004-11-19T22:18:51Z INFO LL_WM_HOST_RESOLVED
2004-11-19T22:18:51Z WARNING Unknown host
2004-11-19T22:18:51Z WARNING Userserver name callback returned during invalid state!
2004-11-19T22:21:16Z INFO send_logout_request
2004-11-19T22:21:16Z INFO Disconnecting viewer!
That's all of that I am gonna post right now. If you want to see more (or the debug_log) let me know.
Incidentally, all that logging makes me a bit nervous but that's another post.

3. Hit the forums (HI!) and started searching. Found the Troubleshooting FAQ (http://www.tyrellcorporation.org/disabled/Troubleshooting) and opened up the ports on my firewall. Started with the limited opening 12020-12050 and 13000-13050. Didn't work. Then because I am stubborn I changed it to 12020 - 13050. Still didn't work. Yes, I even tried 443 although I doubted that would make a difference. It didn't.
4. Just to be absolutely sure I could "hear" incoming on those ports, I did a little testing. Not a problem.
5. Switched it back to the limited port range on my firewall.
6. Smoked, paced and cussed a few times.
7. Repeated number 6 for good measure.
8. Toyed with various preferences settings to no avail.
And now here I am posting to you lovely people! If you can help, fabulous! Otherwise I am gonna have to contact support and harass them.

Many thanks!
Betty