Index: trunk/src/org/openstreetmap/josm/gui/dialogs/relation/actions/PasteMembersAction.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/dialogs/relation/actions/PasteMembersAction.java	(revision 10846)
+++ trunk/src/org/openstreetmap/josm/gui/dialogs/relation/actions/PasteMembersAction.java	(revision 10847)
@@ -8,4 +8,5 @@
 import javax.swing.TransferHandler.TransferSupport;
 
+import org.openstreetmap.josm.Main;
 import org.openstreetmap.josm.gui.datatransfer.ClipboardUtils;
 import org.openstreetmap.josm.gui.dialogs.relation.IRelationEditor;
@@ -33,5 +34,9 @@
     @Override
     public void actionPerformed(ActionEvent e) {
-        new MemberTransferHandler().importData(getSupport());
+        try {
+            new MemberTransferHandler().importData(getSupport());
+        } catch (IllegalStateException ex) {
+            Main.error(ex);
+        }
     }
 
@@ -42,5 +47,9 @@
     @Override
     protected void updateEnabledState() {
-        setEnabled(new MemberTransferHandler().canImport(getSupport()));
+        try {
+            setEnabled(new MemberTransferHandler().canImport(getSupport()));
+        } catch (IllegalStateException ex) {
+            Main.error(ex);
+        }
     }