I have done additional testing. I imported the html code for the theme.php (from a website where it works) and placed it into wp-content/extensions/newsletter/emails/themes, then renamed it and changed the html-code in theme.php. The additonal theme shows correctly on the website, but again same problem. May I upload the html-code so that you can have an eye on it to see whether something in the code (which is working in other places to send out newsletters) is creating these difficulites ? Thanks for your help, Walter