diff --git a/lib/_debugger.js b/lib/_debugger.js
index 41d3fc4210..b8a3177d68 100644
--- a/lib/_debugger.js
+++ b/lib/_debugger.js
@@ -1360,6 +1360,12 @@ Interface.prototype.setBreakpoint = function(script, line,
     script = this.client.currentScript;
   }
 
+  if (script === undefined) {
+    this.print('Cannot determine the current script, ' +
+        'make sure the debugged process is paused.');
+    return;
+  }
+
   if (/\(\)$/.test(script)) {
     // setBreakpoint('functionname()');
     var req = {