The Data Center Security 6.7 installation media comes with legacy agents for Windows 2000 and Windows NT. The silent install of these legacy agent generates an "invalid certificate file" error however the installation succeeds and the agent is fully functional.
*** INPUT VALIDATION ERROR! invalid certificate file. Must be corrected before agent can connect to server.
A defect in the validation of the silent input parameters for agent installer.
Data Center Security (DCS) 6.7.x Manager & UMC
Windows based legacy agents (version 5.2.4.x)
This issue was fixed for version 18.104.22.1688 onwards however this fix was not back ported to earlier version such as the legacy agents for Windows 2000 and Windows NT that ship with Data Center Security (DCS) 6.7.x Manager & UMC. However, the error message is benign and does not affect the functionality or outcome of the installer or agent-manager communication itself, the error can be ignorred.