When you try to uninstall the second named instance of Microsoft SQL Server 2005, you receive the following error message:
Could not open key: UNKNOWN\Installer\Assemblies\D:|Program Files|Microsoft SQL Server|90|Setup Bootstrap|BPA|Repository|YUK1_UPGBLKR|bin|bpa.YUK1_UPGBLKR.dll. Verify that you have sufficient access to that key, or contact your support personnel.
Note The computer has a default instance and two named instances of SQL Server 2005 installed. You uninstall all instances of SQL Server one after another.
This problem may occur when many assemblies are unpublished continuously one after the other.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.