Can't add REST request in test case

hi!

i can't add REST requests in TestCase. i don't understand why. i can add some methods, but not all of them.
even more funny is, that i was able to add them earlier today, but can't do this now.
for example, i can't add "delete_conference Request 1" into "TestCase 1", but i was able to do this 5 hours earlier.
please help me.

here are some logs:
Thu Aug 19 15:30:52 CEST 2010:ERROR:An error occured [java.lang.NullPointerException], see error log for details

Thu Aug 19 15:30:52 CEST 2010:ERROR:java.lang.NullPointerException
java.lang.NullPointerException
at com.eviware.soapui.impl.wsdl.testcase.WsdlTestCase.ensureUniqueName(WsdlTestCase.java:308)
at com.eviware.soapui.impl.wsdl.testcase.WsdlTestCase.insertTestStep(WsdlTestCase.java:487)
at com.eviware.soapui.impl.wsdl.testcase.WsdlTestCase.insertTestStep(WsdlTestCase.java:478)
at com.eviware.soapui.impl.rest.actions.request.AddRestRequestToTestCaseAction.addRequest(AddRestRequestToTestCaseAction.java:85)
at com.eviware.soapui.impl.rest.actions.request.AddRestRequestToTestCaseAction.perform(AddRestRequestToTestCaseAction.java:62)
at com.eviware.soapui.impl.rest.actions.request.AddRestRequestToTestCaseAction.perform(AddRestRequestToTestCaseAction.java:38)
at com.eviware.soapui.support.action.swing.SwingActionDelegate.actionPerformed(SwingActionDelegate.java:104)
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.Component.dispatchEvent(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)

soapUI Pro 3.5.1, copyright (C) 2007-2010 eviware.com http://www.soapui.org | http://www.eviware.com Build daily-2010-04-29-[1], Build Date 2010/04/29 06:26

with best regards,
beno