Hi Amane,
How do you do silent installation?
Normally, I must run "Troubleshoot compatibility" and fill in some required information to install it on windows 8.1. DLP endpoint agent version 12.0 or older versions are very easy to deploy through Altiris and SMC but DLP version 12.5 isn't.
Can you try to disable Elevation under UAC on windows 8.1/8.0 and try again in silent installation?
Thank you :)