Session plugin exception

Session 1.4.2 plugin exception depends of com.microstar.xml package.

10:04:24 PluginJAR: Error while starting plugin sessions.SessionsPlugin
10:04:24 PluginJAR: java.lang.NoClassDefFoundError: com/microstar/xml/XmlHandler
10:04:24 PluginJAR: at sessions.SessionManager.<init>(SessionManager.java:99)
10:04:24 PluginJAR: at sessions.SessionManager.getInstance(SessionManager.java:89)
10:04:24 PluginJAR: at sessions.SessionsPlugin.start(SessionsPlugin.java:67)
10:04:24 PluginJAR: at org.gjt.sp.jedit.PluginJAR.startPlugin(PluginJAR.java:1360)
10:04:24 PluginJAR: at org.gjt.sp.jedit.PluginJAR.activatePlugin(PluginJAR.java:737)
10:04:24 PluginJAR: at org.gjt.sp.jedit.PluginJAR.activatePluginIfNecessary(PluginJAR.java:807)
10:04:24 PluginJAR: at org.gjt.sp.jedit.PluginJAR.load(PluginJAR.java:193)
10:04:24 PluginJAR: at org.gjt.sp.jedit.pluginmgr.ManagePanel$PluginTableModel.setValueAt(ManagePanel.java:532)