Some Antivirus wont allow you to install Rai-blocks or other such files and they consider .exe files to be virus. The best way to install is that you disable the antivirus for some time and install the Raiblock and then re-enable the antivirus.
It seems quite bit good advice, try what the above mentioned to install it again, nothing to loose if you will try, at least if it is work, after you reinstall again your anti-virus, scanning will be happen again, who knows after you doing it, will be good in the end results.