exactly what i said
so you have to change every "." by the full pathname.
if you change it in the .reg file, make sure you use DOUBLE baskslashes.
if your game is installed in "C:\Program Files\Maxis\The Sims" then you have to change
"SIMS_SOUND"=".\\SoundData"
to
"SIMS_SOUND"="C:\\Program Files\\Maxis\\The Sims\\SoundData"
the same thing for the other 3 lines.
got it?