cooja Can't create new motes

Whenever I reload a simulation i am not avle to create any more motes. A new simulation has no problems till i reload. I am working on a Linux Mint 18.3 Java: openjdk version "1.8.0_171" OpenJDK Runtime Environment (build 1.8.0_171-8u171-b11-0ubuntu0.16.04.1-b11) OpenJDK 64-Bit Server VM (build 25.171-b11, mixed mode)

Stacktrace: [java] FATAL [AWT-EventQueue-0] (Cooja.java:2183) - Exception when creating mote type [java] org.contikios.cooja.MoteType$MoteTypeCreationException: No identifier [java] at org.contikios.cooja.mspmote.SkyMoteType.configureAndInit(SkyMoteType.java:135) [java] at org.contikios.cooja.Cooja.doCreateMoteType(Cooja.java:2178) [java] at org.contikios.cooja.Cooja.doCreateMoteType(Cooja.java:2157) [java] at org.contikios.cooja.Cooja$GUIEventHandler.actionPerformed(Cooja.java:2938) [java] at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022) [java] at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348) [java] at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402) [java] at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259) [java] at javax.swing.AbstractButton.doClick(AbstractButton.java:376) [java] at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:842) [java] at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:886) [java] at java.awt.Component.processMouseEvent(Component.java:6533) [java] at javax.swing.JComponent.processMouseEvent(JComponent.java:3324) [java] at java.awt.Component.processEvent(Component.java:6298) [java] at java.awt.Container.processEvent(Container.java:2238) [java] at java.awt.Component.dispatchEventImpl(Component.java:4889) [java] at java.awt.Container.dispatchEventImpl(Container.java:2296) [java] at java.awt.Component.dispatchEvent(Component.java:4711) [java] at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4897) [java] at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4534) [java] at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4475) [java] at java.awt.Container.dispatchEventImpl(Container.java:2282) [java] at java.awt.Window.dispatchEventImpl(Window.java:2746) [java] at java.awt.Component.dispatchEvent(Component.java:4711) [java] at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:760) [java] at java.awt.EventQueue.access$500(EventQueue.java:97) [java] at java.awt.EventQueue$3.run(EventQueue.java:709) [java] at java.awt.EventQueue$3.run(EventQueue.java:703) [java] at java.security.AccessController.doPrivileged(Native Method) [java] at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80) [java] at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:90) [java] at java.awt.EventQueue$4.run(EventQueue.java:733) [java] at java.awt.EventQueue$4.run(EventQueue.java:731) [java] at java.security.AccessController.doPrivileged(Native Method) [java] at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80) [java] at java.awt.EventQueue.dispatchEvent(EventQueue.java:730) [java] at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:205) [java] at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116) [java] at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105) [java] at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101) [java] at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93) [java] at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)