Royal TS is a .NET assembly compiled to "Any CPU" and runs as a 32-bit process on a 32-bit platform and as a 64-bit process on 64-bit platform. So on 64-bit machines, Royal TS is a 64-bit process and the web browser component (Internet Explorer) also runs in 64-bit mode. Some plug-ins may not work on 64-bit IE and needs you to run in 32-bit mode.
You can use Microsoft's CorFlags utility to force Royal TS to run as a 32-bit process on 64-bit Windows.
With the following command executed in an elevated command prompt you set back Royal TS to 32-bit:
corflags.exe RTS3App.exe -32BITREQ+