Wicket jquery ui spinner

Implementation spinner(wicket-jquery-ui-core) on my page:

 297 Spinner<Integer> spinner = new Spinner<Integer>("spinner", new
 298   PropertyModel<Integer>(this, "spin"),
 299            Integer.class);
 300    formProd.add(spinner);
 301   
 302    add(formProd);

But with opening page browser showing "HTTP ERROR 500". Stack-trace printed only in browser, in eclipse is nothing. If spinner remove, everything excellent works. Stack trace:

    HTTP ERROR 500

Problem accessing /wicket/page. Reason:

    Server Error

Caused by:

java.lang.NoClassDefFoundError: org/apache/wicket/IClusterable
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ClassNotFoundException: org.apache.wicket.IClusterable
    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)
    ... 54 more

Caused by:

java.lang.ClassNotFoundException: org.apache.wicket.IClusterable
    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)
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at com.googlecode.wicket.jquery.ui.form.spinner.Spinner.<init>(Spinner.java:112)
    at by.dk.training.items.webapp.pages.packages.formforreg.RegistryPackPanel.onInitialize(RegistryPackPanel.java:297)

    at java.lang.Thread.run(Thread.java:745)

Powered by Jetty://

Spinner for wicket here http://ift.tt/22mfywS Sorry for my English. What could be the reason? Thanks..