Product:
Cognos Planning 10.1.1
Windows 2008 R2 server
Microsoft SQL 2008 R2

Symptom:
Error when starting cognos service after new install of Cognos Planning 10.1.1
No errors in windows event log or cogserver.log file are created.

Error message:
CLASS NOT REGISTERED

Solution:

Register CFGAPICOM.dll from the /bin directory of Cognos 10 :
– In Windows Explorer, go to c:\windows\system32,
– Right-click “cmd.exe” and select “Run as Administrator”
– Go to folder ..\program files (x86)\ibm\cognos\c10\bin\
– Run the DOS command:
regsvr32.exe CFGAPICOM.dll

If that does not help, try below:

Log on to Windows server as local administrator
Go to folder ..\cognos\c10\bin
Create a text file and enter the following line:

FOR %%1 IN (*.DLL) DO REGSVR32 /S %%1

Save the file as regdll.cmd
Start a commando prompt by right click on command prompt and select run as administrator
change to the ..\bin folder
enter regdll to start the script
(it will now registered all the dll files in that folder again)
Wait a few minutes until it is finished.

Then try again to start the Cognos services.