For Environment Scenario #1, if applying the Intelligent Updater does not succeed:

• While in Terminal, type cd /Library/Application Support/Symantec/AntiVirus/Engine
• Enter the following command to list details about the folder: ls -al
• Look for the following files and verify whether the permissions are correct, as shown below:
  -rw-r--r--   1 root  admin    337744 Feb 23 17:33 navenmac.dlb
  -rw-r--r--   1 root  admin   3379384 Feb 23 17:33 navexmac.dlb
• If the permissions read -r--r--r-- they are incorrect. To correct them use the following command: chmod 644 *.dlb

If any other engine folders exist (for example Engine20101004) examine the permissions of those .dlb files as well and correct if necessary.

For Environment Scenario #2, update to SEP for Macintosh 11.0.6 or greater, or to SAV for Macintosh 10.2 for Macintosh for full Mac OS X 10.5 (Leopard) compatibility. This release includes a version of LiveUpdate (5.x) that also compatible with Mac OS X 10.5 (Leopard).

Information on obtaining program version updates or upgrades can be found in the following Knowledge Base article:
"Obtaining an upgrade or update for Symantec AntiVirus Corporate Edition or Symantec Client Security"
http://www.symantec.com/docs/TECH116678

Please note:

Symantec AntiVirus Corporate Edition 10.1.1 and earlier is not supported or compatible with Macintosh OS X version 10.5 (Leopard)

If the drive in question is a non-default, HFS Extended (Journaled, Case Sensitive) volume, the update process will fail. The drive will need to be reformatted as a standard HFS Extended (Journaled) drive.