Index: branches/eam_branches/ipp-20191011/Nebulous/bin/neb-cull
===================================================================
--- branches/eam_branches/ipp-20191011/Nebulous/bin/neb-cull	(revision 40991)
+++ branches/eam_branches/ipp-20191011/Nebulous/bin/neb-cull	(revision 40992)
@@ -59,7 +59,9 @@
 # print "@cull_args\n";
 
-
 if ($one_only) {
     my $status = $neb->there_can_be_only_one(@cull_args);
+    if (not defined $status) {
+        die "not enough instances of Nebulous key: $key";
+    }
     if ($status == 0) {
         die "not enough instances of Nebulous key: $key";