diff --git a/lib/script.js b/lib/script.js
index ccc80f5..6bafe8c 100644
--- a/lib/script.js
+++ b/lib/script.js
@@ -124,7 +124,7 @@ Script.fromString = function(str) {
         });
         i = i + 2;
       } else {
-        throw new Error('Invalid script');
+        throw new Error('Invalid script: '+JSON.stringify(str));
       }
     } else if (opcodenum === Opcode.map.OP_PUSHDATA1 ||
       opcodenum === Opcode.map.OP_PUSHDATA2 ||