DPR-ERR-2002;Unable to execute the request

Cognos BI 10.1.1 (64 bit)
Oracle 11g
Windows Server 2008 R2

Test of data source give error for Oracle JDBC dynamic query mode.
The oracle compatible query mode works fine.

Error message:
DPR-ERR-2002;Unable to execute the request because there was no process available within the configured time limit. The server may be busy.
Handler trace back: [the_dispatcher] com.cognos.pogo.handlers.performance.PerformanceIndicationHandler [the_dispatcher] com.cognos.pogo.handlers.logic.ChainHandler [service_lookup] com.cognos.pogo.handlers.engine.ServiceLookupHandler [load_balancer] com.cognos.pogo.handlers.logic.ChainHandler [lb_forwarder] com.cognos.p2plb.clerver.LoadBalanceHandler….

The wrong JAR file is in use.

On the Cognos BI server install the Oracle 11g client.
Ensure that you have the tnsnames.ora file in the \oracle\instantclient11g\network\admin folder.

To configure Oracle connectivity for use within IBM Cognos 10
installed on Microsoft Windows 2008 server using a 1.6 version of Java, follow
these instructions:

From the Oracle install directory c:\oracle\instantclient11g\ copy the ojdbc6.jar file.
Paste the ojdbc6.jar file to \program files\ibm\cognos\c10_64\v5dataserver\lib folder in the IBM Cognos 10 server.

The ..\cognos\c10_64\webapps\p2pd\WEB-INF\lib directory is used when the Content Store database is in a Oracle server – then you need to have the ojdbc6.jar file here to.
The ..\v5dataserver\lib directory is only used by the Cognos Dynamic Query Mode.

Do NOT paste the ojdbc6.jar file into the cognos\c10_64\webapps\p2pd\WEB-INF\lib folder.
Copy the ocijdbc11.dll from the Oracle client directory \oracle\instantclient11g\ to the
\program files\ibm\cognos\c10_64\bin64 folder.

In order for the Oracle driver to be picked up by IBM Cognos
10, the IBM Cognos 10 service will need to be stopped and started.

If you place the 32 bit ojdbc6.jar file into the cognos\c10_64\webapps\p2pd\WEB-INF\lib folder, instead of the .. cognos\v5dataserver\lib folder , the DQM will work. But it is not a correct setup.

You must have the path to the Oracle client ,c:\oracle\instantclient11g\bin, in PATH.
You need to create a SYSTEM VARIABLE called TNS_ADMIN that should point to the ora files folder; c:\oracle\instantclient11g\network\admin

You change in Cognos Configuration if you want to use 64 bit DQM.
1) Open IBM Cognos Configuration
2) Under the Environment section set the “Report Server Execution
Mode” to 64 bit.
3) Save the configuration
4) Restart the services.
(you need to have 64 bit oracle client installed)

More Information:
If you get a XQE-GEN-2002 error then you have placed a 64 bit oracle dll in folder \program files\ibm\cognos\c10_64\bin64.

Copy the right 32 bit ocijdbc11.dll from oracle folder in to the c10_64\bin64 folder.

Understanding How IBM Cognos 10 Connects to Oracle :
For this data source, the IBM Cognos 10 Compatible Query Mode requires
the installation of the Oracle client software. The IBM Cognos 10
Dynamic Query Mode on the other hand only requires access to the
Oracle type 4 JDBC driver. The name of the Oracle JDBC driver to use
depends on the version of Java being used within the IBM Cognos 10

ojdbc6.jar file is 2102 KB in size for 32 bit version
ocijdbc11.dll file is 135 KB in size for 32 bit version