Error after execution and views opened

Hi,
I installed KNIME with WEKA extension on Ubuntu 14.04. Everything works well, until nodes views are shown (popup with data is displayed correctly). The whole program freezes and only option is to kill the process.

I found out, that in console it prints out "MEvent. CASE!" few dozen times OR ends on following message:

Exception in thread "Thread-13" org.eclipse.swt.SWTException: Invalid thread access
    at org.eclipse.swt.SWT.error(SWT.java:4441)
    at org.eclipse.swt.SWT.error(SWT.java:4356)
    at org.eclipse.swt.SWT.error(SWT.java:4327)
    at org.eclipse.swt.widgets.Widget.error(Widget.java:476)
    at org.eclipse.swt.widgets.Widget.checkWidget(Widget.java:414)
    at org.eclipse.swt.custom.CTabFolder.setSelectionForeground(CTabFolder.java:3328)
    at org.eclipse.ui.internal.presentations.PaneFolder.setSelectionForeground(PaneFolder.java:761)
    at org.eclipse.ui.internal.presentations.defaultpresentation.DefaultTabFolder.updateColors(DefaultTabFolder.java:467)
    at org.eclipse.ui.internal.presentations.defaultpresentation.DefaultTabFolder.shellActive(DefaultTabFolder.java:483)
    at org.eclipse.ui.internal.presentations.util.PresentablePartFolder$2.shellDeactivated(PresentablePartFolder.java:70)
    at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:111)
    at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
    at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4454)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1388)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1412)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1393)
    at org.eclipse.swt.widgets.Shell.filterProc(Shell.java:780)
    at org.eclipse.swt.widgets.Display.filterProc(Display.java:1586)

Any ideas what the problem might me?