Sophos Anti-Virus for Windows displays the following error in the System event log and SAV log
Error e03d0044 The on-access driver could not create a transaction context
This error indicates that a scanning error occurred for a file that was involved in an NTFS transaction.
Known to apply to the following Sophos product(s) and version(s)
Sophos Anti-Virus for Windows 2000+
What To Do
No action is required.
This issue has been resolved with Vista SP1.