SMIL for MaC OS users

Is there anybody who can help me?!!!
I'm producing SMIL (with 4 regions: video rm, text and 2 images regions in rp).
I've an HTML page wic opens inside a .smi file. 
I can open it, without problems, with Windows.
The same one, with MaC gives me many problems.
First of all I cannot open files from Cd; I've to copy all the stuff from Cd to Mac.
If I click on HTML or directly on .SMI file it doesn't work.
I have firse to open RealPlayer, then to open .smil file.
Do you know why?!!!!

NB: My .SMI file begins with:
<smil xmlns="http://www.w3.org/2001/SMIL20/Language"       xmlns:rn="http://features.real.com/2001/SMIL20/Extensions">