This blog relates to deployment of software via Altiris Notification Server 7, using Managed Software Delivery policies, to any Windows 64-bit editions. It applies when the package is a piece of 64-bit software, and you are trying to use a Registry detection rule (e.g. the software installer is not Windows Installer software and you need to use some other detection rule type).
If you try to use a Registry detection rule to detect a registry key under "HKEY_LOCAL_MACHINE\SOFTWARE", the compliance check/software detection may fail and the software may be unnecessarily reinstalled by the Symantec Management Agent.
The reason for this could be that the Symantec Management Agent (which does the actual detection) is 32-bit software running under Wow64 (32-bit emulation mode) on the Windows 64-bit host.
The Symantec Management Agent will be seeing the "HKEY_LOCAL_MACHINE\SOFTWARE" registry entries that are actually located...