eNewsletter plugin editing problem


we have a strange problem with e-Newsletter. We can't edit newsletters from ID 142 on. The changes aren't saved and also the preview is not shown.

If i add a new newsletter... i can edit it normaly... but if i clone the newsletter and then make changes to the cloned one... the changes are saved to the original (the one i cloned from).

Have you any clue what could happend to couse this behavor?