SysInternals to the rescue again! I was able to overcome this issue also by using streams.exe from SysInternals.

C:\Program Files (x86)\SAS\Add-InForMicrosoftOffice\7.1\Custom>streams.exe -d SA
S.Tasks.Examples.SimpleCodeEditor.dll

Streams v1.56 - Enumerate alternate NTFS data streams
Copyright (C) 1999-2007 Mark Russinovich
Sysinternals - www.sysinternals.com

C:\Program Files (x86)\SAS\Add-InForMicrosoftOffice\7.1\Custom\SAS.Tasks.Example
s.SimpleCodeEditor.dll:
Deleted :Zone.Identifier:$DATA