Object reference not set to an instance of an object

Cognos Controller 8.4

When user changes company in there Data Entry reporting session they get an error message and then Excel is hanging.
In this environment the controller client is started from the ccr.exe file that is installed on the citrix servers with use of the ccrlocalclient.msi package.

Error found on client in Windows Event log:

Event Type: Warning
Event Source: Cognos Controller
Event Category: None
Event ID: 0
Date: 2009-12-07
Time: 10:27:31
User: N/A
Computer: CITRIX1
Standard Error
Source: ControllerForms
Description: OpenWorkbook
Object reference not set to an instance of an object.
at Cognos.Controller.ControllerForms.clsDataEntry.ActivateDataEntryForm()
at Cognos.Controller.ControllerForms.clsDataEntry.OpenSelectedForm(UserParameters& UserSelection)

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

The NET framework 2.00 on the Cognos Controller Client does not have full trust to the Cognos Controller Application Server.
On the computer you can check if the FULLTRUST is set to the server by run the commando CASPOL –LG from the command prompt.
Go to the command prompt
Go to the folder c:\windows\microsoft.net\framework\v2.0.50727
Enter caspol –lg
You will see a list of the connections to FULLTRUST.
Check the last lines of code group to find the Controller app server name to be listed.

On the Cognos Controller Client Computer ( citrix server ) run a commando to set the trust to the server.
Create a text file (named setcaspol.cmd) on a share on the Cognos Controller server:

cd c:\windows\microsoft.net\framework\v2.0.50727

Caspol.exe -m -q -ag All_Code -url http://cognosserver/cognos8/* FullTrust -n name1a
Caspol.exe -m -q -ag All_Code -url* FullTrust -n name1b
Caspol.exe -m -q -ag All_Code -url http://cognosserver.domain.com/cognos8/* FullTrust -n name1c

Caspol.exe -e off

In above file you need to change “cognosserver” with you controller app server name.
Then run the setcaspol.cmd file from the Citrix servers, to set the trust in NET framework 2.00.

From the start menu – select run
Enter the \\servername\share to connect to the share there the setcaspol.cmd file is saved.
Double click on the setcaspol file to run it on the Client computer (citrix server)
You should briefly see 4 “Success” roll by, if the script is working.