error in visualization

[Ithinky]

Thank you for your useful tool ! I used CP as input and found 2 valid trees, but I have trouble in visualization.The log is as follows. Can you help me? Thanks!

Found 2 valid tree(s) Exception in thread "main" java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader.main(JarRsrcLoader.java:58) Caused by: java.awt.HeadlessException at sun.awt.HeadlessToolkit.getScreenResolution(HeadlessToolkit.java:226) at util.LineageDisplayConfig.node2DOT(LineageDisplayConfig.java:262) at util.LineageDisplayConfig.toDOT(LineageDisplayConfig.java:286) at lineage.LineageEngine.buildLineage(LineageEngine.java:149) at lineage.LineageEngine.main(LineageEngine.java:396) ... 5 more