I have only installed 'Viewer' on a W7 32 bit OS, but when I run the MSI configuration tool from this 'Viewer' installation and click on the 'rut.host5.6en.msi' already downloaded into a folder, I get the message 'It is not the correct package'. In the forum the solution suggests 'remove the Host installation on the machine' As far as I am aware I only installed the 'Viewer'. There is no additional software from Usoris in programs and features.
First, double check if you have the latest Viewer installed and Host package downloaded. As of now, March 4 2014 the latest version is 184.108.40.206.
Secondly, make sure that you don't do any prior configurations on that Host file , because the default option for the Standard MSI option is to overwrite the Host package. So you might end up with an already configured Host package accidentally. In other words, it should be a purely vanilla Host package freshly downloaded from the site.