JavaFXが利用できない（実行時エラー）

###前提・実現したいこと
(例)Javaの演習書を読みながら、GUIアプリを作成しようとしています。
ライブラリの参照でさっそくつまずいてしまいました。

GUI用のJavaファイル”controlsfx-8.0.5.jar”をダウンロードし、
フォルダ"C:\ProgramFiles\Java\javalib_20170427added"内に保存しました。
Javaプロジェクトにて、ライブラリに上記のファイルを参照設定しました。
これにより、javaファイル内のDialogクラスを使っている部分のコンパイルエラー（参照がありませんという内容）は解消されましたが、実行時にエラーが出てしまいます。ボタンをクリックするとダイアログが出るプログラムなのですが、ボタンを押下すると実行時エラーが出てしまいます。

エラーには以下の内容が書かれています。解決方法について教えていただきたいです。

###発生している問題・エラーメッセージ
compile:
（省略）
Detected JavaFX Ant API version 1.3
Launching fx:jar task from C:\Program Files\Java\jdk1.8.0_91\jre..\lib\ant-javafx.jar
Warning: From JDK7u25 the Codebase manifest attribute should be used to restrict JAR repurposing.
Please set manifest.custom.codebase property to override the current default non-secure value '*'.
Launching fx:deploy task from C:\Program Files\Java\jdk1.8.0_91\jre..\lib\ant-javafx.jar
ベースJDKがありません。パッケージはシステムJREを使用します。
ベースJDKがありません。パッケージはシステムJREを使用します。
jfx-deployment-script:
jfx-deployment:
jar:
（省略）
jfx-project-run:
Executing （省略）
C:\Program Files\Java\jdk1.8.0_91\jre/bin/java
Exception in thread "JavaFX Application Thread" java.lang.NoClassDefFoundError: com/sun/javafx/Utils
at org.controlsfx.tools.Platform.getCurrentPlatform(Platform.java:65)
at org.controlsfx.tools.Platform.<clinit>(Platform.java:41)
at org.controlsfx.dialog.HeavyweightDialog.<clinit>(HeavyweightDialog.java:70)
at org.controlsfx.dialog.Dialog.<init>(Dialog.java:340)
at org.controlsfx.dialog.Dialogs.buildDialog(Dialogs.java:1009)
at org.controlsfx.dialog.Dialogs.showSimpleContentDialog(Dialogs.java:1029)
at org.controlsfx.dialog.Dialogs.showInformation(Dialogs.java:553)
at guitest01.GuiTest01$1.handle(GuiTest01.java:36)
at guitest01.GuiTest01$1.handle(GuiTest01.java:27)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Node.fireEvent(Node.java:8411)
at javafx.scene.control.Button.fire(Button.java:185)
at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:182)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:96)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:89)
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3757)
at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3485)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2494)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:380)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:294)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(GlassViewEventHandler.java:416)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:415)
at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
at com.sun.glass.ui.View.notifyMouse(View.java:937)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ClassNotFoundException: com.sun.javafx.Utils
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 56 more