Product:
Cognos BI 10.1.1
Cognos Controller 10.1.1
Windows 2008 R2 Server
Internet Explorer 10

Symptom:
When user surf to Cognos connection and try to login they get a error message.
You have more than one Cognos System that you work with at the same time, so you surf to Cognos Connection in one Internet Explorer session, and work with the other Cognos environment in a different tab of Internet Explorer.

Error message:
DPR-ERR-2107 – The User Capabilities Cache cookie cannot be decoded

Possible Solution:
For Each Cognos Environment do the following:
Logon to server as local administrator
Check the URL the users use to surf to the Cognos connection.
http://servername.domain.com/ibmcognos
Open IBM Cognos Configuration on the server, right click and select “run as administrator”.

Open Actions menu, then click on Edit Global Settings

Click the General tab

Under Cookie Settings, enter the details for “Domain” and “Path”
Domain = servername.domain.com (this should be unique for each environment)
Path = ibmcognos
Click save from inside Cognos configuration.
Restart the Service.

Do this for each environment.
One for Cognos BI and one for Cognos Controller, if they do not share Cognos BI server.

Test that Cognos Framework manager works to login after the change.