You have uninstalled DCS Agent and reboot the OS but after the next installation attempt you are receiving an error that reboot is pending.
Error! An agent uninstallation requires a reboot. Please reboot system before running installation
Release : All
Component : DCS Agent
There is a remaining registry value name Uninstall SIS Agent DCSAgentRebootPending in the registry location below that is preventing the DCS Agent installation.
Delete the registry value Uninstall SIS Agent and retry the installation