There is no bug in "compare", I guess it must be a problem with snd_playing(wh2) != 1 even when the sound is playing. Maybe the function returns some non-zero value, f.i. 3.1415, instead of 1, even though the manual says it should return 1 when the sound is playing.
"Falls das Resultat nicht einfach nur dermassen gut aussieht, sollten Sie nochmal von vorn anfangen..." - Manual
