On Windows 7, you may have the following error stated in your eventlog:
Log Name: System
Source: Microsoft-Windows-DistributedCOM
Event ID: 10016
Level: Error
User: SYSTEM
Description: The application-specific permission settings do not grant Local Launch permission for the COM Server application with CLSID {C97FCC79-E628-407D-AE68-A06AD6D8B4D1} and APPID {344ED43D-D086-4961-86A6-1106F4ACAD9B} to the user NT AUTHORITY\SYSTEM SID (S-1-5-18) from address LocalHost (Using LRPC). This security permission can be modified using the Component Services administrative tool.