Error message while trying to save a 'target text file' in SDL2015

Hello,

I am using SDL Studio 2015.

Today for the first time during my work with SDL Studio over almost three years, I got an error message while trying to save the "target text" during translation,

The error message is:

"Zuieltext konnte nicht gespeichert werden, Der Objectverweis wurde nicht auf eine instanz festgelegt"

Sorry, for this German error message text, but this is beacuse I am using the German language option in my SDLStudio.

How can  overcome this problem please.

Any help/tipp would be useful. Thanks for your help in advance

Regards, S. Gupta