Message cannot be loaded

Hi,

i'm trying to test a message mapping which i created, and imported a xml-Message. If I don't save this message, i can test with it without problems. But as soon as i want to save my testdata, a problem occured and the repository told me: "Message cannot be loaded"; nothing more...

Does anyone know about this problem and has an idea to solve it?

A first idea was that the message is too large, but after i cut it, the message remains still the same. The only possibility is to abolish all the changes i made since the last saving before.

Thank You for your help,

Regards, Leo