diff --git a/util/error.js b/util/error.js
index 428fc89..4e5097f 100644
--- a/util/error.js
+++ b/util/error.js
@@ -9,7 +9,8 @@ function MissingSourceError(msg, missingTxHash) {
   // TODO: Since this happens in normal operation, perhaps we should
   //       avoid generating a whole stack trace.
   Error.call(this);
-  Error.captureStackTrace(this, arguments.callee);
+// This is not compatible with firefox.
+//  Error.captureStackTrace(this, arguments.callee);
   this.message = msg;
   this.missingTxHash = missingTxHash;
   this.name = 'MissingSourceError';
@@ -19,6 +20,7 @@ MissingSourceError.prototype.__proto__ = Error.prototype;
 
 exports.MissingSourceError = MissingSourceError;
 
+
 /**
  * Used in several places to indicate invalid data.
  *
@@ -29,7 +31,9 @@ function VerificationError(msg, missingTxHash) {
   // TODO: Since this happens in normal operation, perhaps we should
   //       avoid generating a whole stack trace.
   Error.call(this);
-  Error.captureStackTrace(this, arguments.callee);
+
+// This is not compatible with firefox.
+//  Error.captureStackTrace(this, arguments.callee);
   this.message = msg;
   this.missingTxHash = missingTxHash;
   this.name = 'VerificationError';