eNewsletter plugin - unable to incert images

I have just managed to get e-newletter plugin working with the plugin 'wp-ses' and Amazon SES.
All great and very excited.
My problem is that I am unable to add images to the newsletter. The 'Add Media' button doesnt appear to do anything in the Create Newsletter/Email Content text box.
Am I missing something obvious? Any suggestions ad to what I am doing wrong.