Moving up and down Test cases

Below is the error log:

Fri Dec 05 18:01:18 IST 2014:ERROR:org.apache.xmlbeans.impl.values.XmlValueDisconnectedException
org.apache.xmlbeans.impl.values.XmlValueDisconnectedException
at org.apache.xmlbeans.impl.values.XmlObjectBase.check_orphaned(XmlObjectBase.java:1244)
at com.eviware.soapui.config.impl.ModelItemConfigImpl.isSetId(ModelItemConfigImpl.java:332)
at com.eviware.soapui.impl.wsdl.AbstractWsdlModelItem.getId(AbstractWsdlModelItem.java:148)
at com.eviware.soapui.model.support.ModelSupport.findModelItemById(ModelSupport.java:124)
at com.eviware.soapui.impl.wsdl.teststeps.assertions.support.AssertionEntry.getSource(SourceFile:238)
at com.eviware.soapui.impl.wsdl.teststeps.assertions.support.AssertionEntry.<init>(SourceFile:94)
at com.eviware.soapui.impl.wsdl.teststeps.AssertionTestStep.a(SourceFile:80)
at com.eviware.soapui.impl.wsdl.teststeps.AssertionTestStep.resetConfigOnMove(SourceFile:614)
at com.eviware.soapui.impl.wsdl.testcase.WsdlTestCase.resetConfigOnMove(WsdlTestCase.java:892)
at com.eviware.soapui.impl.wsdl.WsdlTestSuite.moveTestCase(WsdlTestSuite.java:443)
at com.eviware.soapui.impl.wsdl.actions.testcase.MoveTestCaseUpAction.perform(MoveTestCaseUpAction.java:45)
at com.eviware.soapui.impl.wsdl.actions.testcase.MoveTestCaseUpAction.perform(MoveTestCaseUpAction.java:31)
at com.eviware.soapui.support.action.swing.SwingActionDelegate.actionPerformed(SwingActionDelegate.java:93)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.AbstractButton.doClick(Unknown Source)
at javax.swing.plaf.basic.BasicMenuItemUI.doClick(Unknown Source)
at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(Unknown Source)
at java.awt.AWTEventMulticaster.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)