When upgrading Cisco Emergency Responder (CER) 1.2.3, an error message indicates that the OS is less than 2000.2.6, and 2000.2.6sr2 is needed for the upgrade.
This happens even if the installed version of OS is 2000.2.6 or higher.
This occurs because the installer looks into the registry values to check the current OS version installed.
Editing the Windows registry information can solve the problem. You can use regedit for editing the registry information by performing these steps.
To resolve the problem, edit this key to the values shown:
This issue is tracked in Cisco bug ID CSCsa61886.