promoting was attempting to use players promotion class (which is null)

src/engine/objects/PlayerCharacter.java

@@ -2193,7 +2193,7 @@ public class PlayerCharacter extends AbstractCharacter {
     public boolean setPromotionClass(int value) {
 
         PromotionClass promotionClass = PromotionClass.GetPromtionClassFromCache(value);
-        this.absPromotionClass = mbEnums.ClassType.valueOf(this.getPromotionClass().getName());
+        this.absPromotionClass = mbEnums.ClassType.valueOf(promotionClass.getName());
         if (promotionClass == null)
             return false;