This would most likely mean, that installer service required to install programs onto windows OS is not available due to update, incorrect terminiation of previous software installation etc.. Most likely you would run into this if you tried to install any other piece of software. Though i had found this on citrix community page: https://discussions.citrix.com/topic/99136-error-1719-the-windows-installer-service/ But this would require a bit of work on sysadmin part as I am not that familiar with citrix virtualisation, from system perspective, Kentico is just an application which is installed into the OS.