--- ./panel-plugin/xfce-volume-button.c.orig	2012-10-10 16:55:46.000000000 +0200
+++ ./panel-plugin/xfce-volume-button.c	2012-12-03 23:32:03.000000000 +0100
@@ -782,6 +782,10 @@
       case GDK_SCROLL_DOWN:
       case GDK_SCROLL_LEFT:
         /* Decrease one step when scrolling down/left */
+	/* ehaupt: my guess is that the volume becomes 0 or lower and then makes the program crash */ 
+	if(old_value - increment <= 0) {
+		break;
+	}
         gtk_adjustment_set_value (GTK_ADJUSTMENT (button->adjustment), old_value - increment);
         break;
     }