Product:
Cognos Planning 8.4.1

Symptom:
On new install or on an upgrade to Cognos Planning 8.4.1 the Cognos Planning service does not start when you try from inside Cognos Configuration. Cognos 8 BI service will start fine on the other hand.

Cause:
When the SQL database is in an INSTANCE (not using the standard port number of 1433) then you must use the instance name for Cognos Planning to access the database. The use of the SQL port number in Cognos Configuration for the Planning Store database will give this error.
Cognos use java odbc connectors to access the database.

Solution:
Ensure that the SQL Browser service is started on the Microsoft SQL 2005 server

In Cognos Configuration under Planning Store – Database – Resource Properties
Ensure that you address the database server with servername\instance name
e.g. SRVSQL01\COGNOS

The use of SQL Aliases on the Cognos Planning server may not solve this issue.

You can try by installing the Microsoft SQL server 2005 client’s tools on the Application server.
Then from inside the Configuration Tools menu start SQL Server Configuration Manager.
Under the SQL Native Client Configuration right click on Alias and select New Alias.

Create a new alias named planningds for the planning database server.
Enter the server name and the port number.
Port number can be different when you use an instance of Microsoft SQL server on a database server machine.