--- rxvt-unicode/src/rxvtperl.xs	2012/06/14 17:06:57	1.194
+++ rxvt-unicode/src/rxvtperl.xs	2012/06/14 17:16:05	1.195
@@ -97,6 +97,8 @@
       rc.set (s, SvPVbyte_nolen (sv));
       rc.get (c);
     }
+  else
+    croak ("unable to parse colour,");
 
   return c;
 }