Fix for bug 226973. Print Preview Error (Previewing During Page Rendering/No Printer Installed) Shows Print Preview Toolbar.

r+sr=ben

toolkit/components/printing/content/printUtils.js

@@ -188,6 +188,7 @@ var PrintUtils = {
       // causing an exception to be thrown which we catch here.
       // Unfortunately this will also consume helpful failures, so add a
       // dump(e); // if you need to debug
+      return;
     }
 
     var printPreviewTB = document.getElementById("print-preview-toolbar");