Second attempt. Posted yesterday but no trace.
I've installed SRWare Iron v 25.0.1400 on a number of workstations. The Windows 8 ones - ONLY - exhibit the "class not registered" behaviour if I click on taskbar.desktop or start menu (start8) icons. All icons correctly address the program in its folder. Furthermore if I run the program from the full program menu or by doubleclicking the iron.exe in the program folder, it works as advertised. So clearly there isn't "really" a class registration issue, more like a path issue.
In all cases, the problem takes a few hours to manifest. i.e. when freshiy installed, all icons work as they should. After a few hours, however, whether or not the system has been rebooted, the icons cease to function.