Updating with the .jdb files works fine, and I've already updateded to the latest SEPM (at least the latest I can see on the fileconnect site, my version is 11.0.1014.26).
As far as the log file goes, this is what it says (if I go to the URLs specified on the same machine, I get the page no problems):
3/27/2009, 14:34:49 GMT -> Progress Update: DOWNLOAD_FILE_START: URL: "http://liveupdate.symantec.com/liveupdate_3.3.0.78_english_livetri.zip", Estimated Size: 0, Destination Folder: "C:\Documents and Settings\All Users\Application Data\Symantec\LiveUpdate\Downloads"
3/27/2009, 14:34:51 GMT -> CSendHTTPRequest::SendRequest - Unable to connect to the server.
3/27/2009, 14:34:51 GMT -> Progress Update: DOWNLOAD_FILE_FINISH: - NOTE - URL: "http://liveupdate.symantec.com/liveupdate_3.3.0.78_english_livetri.zip", Full Download Path: "C:\Documents and Settings\All Users\Application Data\Symantec\LiveUpdate\Downloads\liveupdate_3.3.0.78_english_livetri.zip" HR: 0x802A0045
3/27/2009, 14:34:51 GMT -> HR 0x802A0045 DECODE: E_UNABLE_TO_REACH_SERVER
3/27/2009, 14:34:51 GMT -> Progress Update: DOWNLOAD_BATCH_FINISH: HR: 0x802A0045, Num Successful: 0
3/27/2009, 14:34:51 GMT -> HR 0x802A0045 DECODE: E_UNABLE_TO_REACH_SERVER
3/27/2009, 14:34:51 GMT -> EVENT - SERVER SELECTION FAILED EVENT - LiveUpdate failed to connect to server liveupdate.symantec.com at path via a HTTP connection. The server connection attempt failed with a return code of 1814, LiveUpdate could not retrieve the catalog file of available Symantec product and component updates.
3/27/2009, 14:34:51 GMT -> Progress Update: TRYING_HOST: HostName: "update.symantec.com" URL: "ftp://update.symantec.com/opt/content/onramp" HostNumber: 2
3/27/2009, 14:34:51 GMT -> Progress Update: DISCONNECT
3/27/2009, 14:34:51 GMT -> Progress Update: TRIFILE_DOWNLOAD_START: Number of TRI files: 0 Downloading LiveUpdate catalog file
3/27/2009, 14:34:51 GMT -> LiveUpdate will download the first Mini-TRI file, liveupdate_3.3.0.78_english_livetri.zip
3/27/2009, 14:34:51 GMT -> Progress Update: DOWNLOAD_BATCH_START: Files to download: 1, Estimated total size: 0
3/27/2009, 14:34:51 GMT -> Progress Update: PRE_CONNECT: Proxy: "(not-available)" Agent: "IPWh6s1kTrhJTKdCsl5GyBMo5vk2uPMSQAAAAA" AccessType: 0x0
3/27/2009, 14:34:51 GMT -> Progress Update: CONNECTED: Proxy: "(not-available)" Agent: "IPWh6s1kTrhJTKdCsl5GyBMo5vk2uPMSQAAAAA" AccessType: 0x0
3/27/2009, 14:34:51 GMT -> Progress Update: DOWNLOAD_FILE_START: URL: "ftp://update.symantec.com/opt/content/onramp/liveupdate_3.3.0.78_english_livetri.zip", Estimated Size: 0, Destination Folder: "C:\Documents and Settings\All Users\Application Data\Symantec\LiveUpdate\Downloads"
3/27/2009, 14:34:53 GMT -> CstInetGetFile::DoTransfer - Unable to connect to the server.
3/27/2009, 14:34:53 GMT -> Progress Update: DOWNLOAD_FILE_FINISH: - NOTE - URL: "ftp://update.symantec.com/opt/content/onramp/liveupdate_3.3.0.78_english_livetri.zip", Full Download Path: "(null)" HR: 0x802A0045
3/27/2009, 14:34:53 GMT -> HR 0x802A0045 DECODE: E_UNABLE_TO_REACH_SERVER
3/27/2009, 14:34:53 GMT -> Progress Update: DOWNLOAD_BATCH_FINISH: HR: 0x802A0045, Num Successful: 0
3/27/2009, 14:34:53 GMT -> HR 0x802A0045 DECODE: E_UNABLE_TO_REACH_SERVER
3/27/2009, 14:34:53 GMT -> EVENT - SERVER SELECTION FAILED EVENT - LiveUpdate failed to connect to server update.symantec.com at path /opt/content/onramp via a FTP connection. The server connection attempt failed with a return code of 1814, LiveUpdate could not retrieve the catalog file of available Symantec product and component updates.
3/27/2009, 14:34:53 GMT -> Progress Update: HOST_SELECTION_ERROR: Error: 0x802A0027