Symptoms
When you install a Microsoft SQL Server 2005 service pack, cumulative update, or cluster hotfix, the installation fails. When this problem occurs, an error message that resembles the following is logged in the Summary.txt file:

Machine: ServerName
Product: Client Components
Error: Failed to install and configure assemblies C:\Program Files\Microsoft SQL Server\90\NotificationServices\9.0.242\Bin\microsoft.sqlserver.notificationservices.dll in the COM+ catalog.
Error: -2146233087
Error message: Unknown error 0×80131501
Error description: The Transaction Manager is not available. (Exception from HRESULT: 0×8004D01B)Note The Summary.txt file is located under the following folder:
%ProgramFiles%\Program Files\Microsoft SQL Server\90\Setup Bootstrap\LOG\HotfixAdditionally, an error message that resembles the following is logged in the SQLTools9_Hotfix_KB921896_sqlrun_tools.msp.log file:

MSI (s) (9C!38) [17:51:18:649]: Product: Microsoft SQL Server 2005 Tools — Error 29549. Failed to install and configure assemblies C:\Program Files\Microsoft SQL Server\90\NotificationServices\9.0.242\Bin\microsoft.sqlserver.notificationservices.dll in the COM+ catalog. Error: -2146233087
Error message: Unknown error 0×8013150
Error description: The Transaction Manager is not available. (Exception from HRESULT: 0×8004D01B)
Error 29549. Failed to install and configure assemblies C:\Program Files\Microsoft SQL Server\90\NotificationServices\9.0.242\Bin\microsoft.sqlserver.notificationservices.dll in the COM+ catalog. Error: -2146233087
Error message: Unknown error 0×8013150
Error description: The Transaction Manager is not available. (Exception from HRESULT: 0×8004D01B)Note The SQLTools9_Hotfix_KB921896_sqlrun_tools.msp.log file is located under the following folder:
%ProgramFiles%\Program Files\Microsoft SQL Server\90\Setup Bootstrap\LOG\Hotfix
Resolution
This problem occurs because the SQL Server Setup program cannot access the Microsoft Distributed Transaction Coordinator (MS DTC) service.