I was installing 12.31 client from msi and got this error during setup. Computer rebooted automatically and everything seems to work. Client is Win7 x64. Everything ok?
I'm afraid something is wrong. Please, make sure, that you have Win7 SP1 with all latest MS updates installed.
There was a problem with WSUS. Client did not have all MS updates. I stopped automatic update service, deleted softwaredistribution folder and started automatic update service. Next installed all MS updates, removed Client Security and rebooted. After that Client Security installed without errors