I too had this problem and have found no way around it, but which game is it specifically, every windows SCI game that I have and that I know of has a DOS version (not sure about SQ4 with speech- but text version is DOS and works fine). I just install the DOS version and run it using VDMSound. They all run fine.
(re: re: Window SCI Engine under Windows XP) I discovered a way around this, which I posted how to in the thread Link: Is there any Windows XP help? (Holmes)(http://community.vugames.com/WebX?14@120.Uvtpbgmb4G3.12@.ef97ec7) on the Sierra King’s Quest VI forums. I was able to get the Windows version of KQ6 going under XP with my method as well as Laura Bow II.