Update PLaunchApp.java

JavaApp/src/main/java/net/kdt/pojavlaunch/PLaunchApp.java

@@ -217,6 +217,8 @@ public class PLaunchApp {
                             }
                         }
                     }
+
+                    assetThrIndex = 0;
                 }
             }
             hasDownloadedFile.getParentFile().mkdirs();