http://blogs.technet.com/b/office_resource_kit/archive/2010/09/21/office-2010-office-customization-tool-and-windows-installer-version.aspxWe've had some questions about the Windows Installer version required by the Office 2010 Office Customization Tool (OCT) and would like to clarify the requirements. In Office 2010, there are two architecture-specific versions of the OCT, one for 32en-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)