If you receive this error when attempting to install arcplan software on a new server,

You will need to upload the Microsoft "root Trusted certificate", which is available for upload here:

http://download.windowsupdate.com/msdownload/update/v3/static/trustedr/en/rootsupd.exe

If on 64Bit machine, unblock the executable, in Properties and then execute it. There is no output from running it.