Next it would worth to read the following 
MSDN: Cabinet files chapter
MSDN: How to use licensed ActiveX controls in Internet Explorer
You don't have to register ViewerX on the server side. What you should do is to have the .cab file hosted on the web server. And in your html code add a refference to the cab file, so it could be downloaded and installed on a client computer. This is common for all ActiveX controls.
A sample html code with ViewerX could look like this:
<object classid="clsid:5220CB21-C88D-11CF-B347-00AA00A28331">
<param name="LPKPath" value="/download/cab/scvncctrl.lpk">
</object>
<object classid="clsid:62FA83F7-20EC-4D62-AC86-BAB705EE1CCD" id="ViewerX" codebase="/download/cab/viewerx.cab">
<param name="HostIP" value='192.168.1.1'>
<em>Your browser does not support ActiveX controls. Use Internet Explorer to view ViewerX demo page.!</em>
</object>