I've found that when I port a game I was working on in the old dos version of AGS over to the newer, better, sexier windows version, the dialoge command "set-speech-view" no longer works, although it works fine in games I've made using only the windows version. It's annoying and odd.
Any ideas?
Did you upgrade to 2.56? There was a bug with set-speech-view in older Windows versions.