diff --git a/toolkit/devtools/server/main.js b/toolkit/devtools/server/main.js
index 73f60ab8779..ab385abf96d 100644
--- a/toolkit/devtools/server/main.js
+++ b/toolkit/devtools/server/main.js
@@ -49,7 +49,9 @@ function loadSubScript(aURL)
       .getService(Ci.mozIJSSubScriptLoader);
     loader.loadSubScript(aURL, this);
   } catch(e) {
-    let errorStr = "Error loading: " + aURL + ": " + e + " - " + e.stack + "\n";
+    let errorStr = "Error loading: " + aURL + ":\n" +
+                   (e.fileName ? "at " + e.fileName + " : " + e.lineNumber + "\n" : "") +
+                   e + " - " + e.stack + "\n";
     dump(errorStr);
     Cu.reportError(errorStr);
     throw e;