"translate as single document" not working

Hi to all, i dragged and dropped the file that i want to translate (tried the browse option too), chose the "translate as single document" and selected the source and target languages. But after that i was unable to move to the next step (choosing TM and starting translation) and even the "ok" button at the bottom of the "translation memory and document settings" box was not working (only "cancel"). Everything was working normally two weeks ago! Is there anything i can do?