Does -slave work on Windows 98?

I'm developing a mplayer front-end using the Qt libraries (smplayer). So
theorically it should work too on Windows 98.

But I've been reported that smplayer doesn't work properly under Windows 98 
and Windows ME.

I installed Win 98 in a virtual machine, and indeed the problem seems that 
mplayer ignores (or doesn't get) the slave commands. I tested with another 
GUI (MPUI) and it has exactly the same problem.

Tested several mplayer builds, including 1.0rc1, with the same result.

Is this a bug in mplayer, or simply it's a limitation of those versions of 
Windows?
-- 
RVM