FileNotFoundException with soapUI 4.0.0

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= SOAPUI_HOME = /home/angel/Aplicaciones/soapui-4.0.0
=
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Configuring log4j from [/home/angel/Aplicaciones/soapui-4.0.0/bin/soapui-log4j.xml]
20:15:40,160 INFO  [DefaultSoapUICore] initialized soapui-settings from [/home/angel/Aplicaciones/soapui-4.0.0/soapui-settings.xml]
20:15:41,830 INFO  [SoapUI] Used java version: 1.6.0_26
Exception in thread "XpcMessageLoop" java.lang.ExceptionInInitializerError
        at com.teamdev.xpcom.a.b.a.a.<init>(Unknown Source)
        at com.teamdev.xpcom.XpcMessageLoop.<init>(Unknown Source)
        at com.teamdev.xpcom.XpcMessageLoop.getInstance(Unknown Source)
        at com.teamdev.xpcom.b$a.run(Unknown Source)
Caused by: java.lang.RuntimeException: java.io.FileNotFoundException: Library libgtk-x11-2.0 not found at any known locations !
        at com.jniwrapper.linux.utils.LinuxLibraryLoader.<init>(LinuxLibraryLoader.java:90)
        at com.jniwrapper.gtk.GtkLib.<init>(GtkLib.java:25)
        at com.jniwrapper.gtk.GtkLib.getFunction(GtkLib.java:41)
        at com.jniwrapper.gtk.GTK.<clinit>(GTK.java:45)
        ... 4 more
Caused by: java.io.FileNotFoundException: Library libgtk-x11-2.0 not found at any known locations !
        ... 8 more