Try rebooting and run the install.
Can you download and run the install from the update page?
If not try running it from the cli
1. Begin the upgrade process by typing the following command:
system upgrade
For example: system upgrade CPPM-upgradeimage.bin
The upgrade process should begin immediately upon executing the above command.
2. After the upgrade is complete, restart the machine using the following CLI command
system restart
The ClearPass Policy Manager will restart and boot up to the latest version, CPPM 6.1.