diff --git a/xpfe/components/xremote/src/XRemoteService.cpp b/xpfe/components/xremote/src/XRemoteService.cpp
index 9aef9e7ded3..ec5efbef690 100644
--- a/xpfe/components/xremote/src/XRemoteService.cpp
+++ b/xpfe/components/xremote/src/XRemoteService.cpp
@@ -568,7 +568,6 @@ XRemoteService::OpenURL(nsCString &aArgument,
   }
 
   else if (newTab && aOpenBrowser) {
-    NS_ASSERTION(bwin && uri, "failed to open remote URL in new tab");
     if (bwin && uri) {
       nsCOMPtr<nsIDOMWindow> container;
       rv = bwin->OpenURI(uri, 0,
@@ -576,6 +575,10 @@ XRemoteService::OpenURL(nsCString &aArgument,
                          nsIBrowserDOMWindow::OPEN_EXTERNAL,
                          getter_AddRefs(container));
     }
+    else {
+      NS_ERROR("failed to open remote URL in new tab");
+      return NS_ERROR_FAILURE;
+    }
   }
 
   else if (bwin && uri) { // unspecified new browser URL; use prefs