The BOL version of Sophos should be pointing to the following primary and secondary update servers:

http://sophos-1.bol.ucla.edu:8500/ESXP (port 8000 for Sophos 5 upgrade installs)
http://sophos-2.bol.ucla.edu:8500/ESXP (port 8000 for Sophos 5 upgrade installs)

If these URLs are not correct, you will need to download and replace the corrupted config files by following these instructions:

1. Download the following zip file: https://www.bol.ucla.edu/pub/bol/sophos/win/Sophos_Removal_Tools/SAV6_cfg.zip

2. Extract the contents of the zip file and place it in one of the following folders:

• C:\ProgramData\Sophos\AutoUpdate\Config (Windows VISTA ONLY)
• C:\Program Files\Sophos\AutoUpdate\Config (Windows XP/2000)

3. Force Sophos to auto update by right clicking the Sophos shield in the taskbar and selecting ‘Update now’.