I can't turn sounds off

Windows XP SP2

WindowBlinds version : WindowBlinds 6.3 (build 67 x86)

WindowBlinds is installed correctly on this PC
WindowBlinds appears to be activated on this PC
Your machine supports per pixel borders on WindowBlinds skins.

(Plug and Play Monitor) 1 is attached to NVIDIA GeForce 6100 nForce 430

Wblind.dll         2008/09/17 08:05:20
Wbsrv.dll         2008/09/16 08:44:42
Wbconfig.exe         2008/09/16 08:44:32
Wbload.exe         2008/04/26 16:14:14
Wbhelp.dll         2008/04/26 16:14:07
Wbui.dll         2008/04/26 16:14:05
Tray.dll              2008/04/26 16:14:21
Screen.exe         2008/07/15 11:31:09

I go to Settings/Override Default Settings and uncheck the "Play Sounds Defined by the Skin" box. Press the "Apply Changes" button, but the sounds still play. Am i doing it wrong?