Cubase 5 - No sound in imported audio files

Hello guys,

please could you help me? When I want to import any audio file there is no sounds already in the preview and when the importing is done, when I want to play the audio, there is no sound. The mixer shows it but no sound comes out.
Do you have any idea where could be the problem?

I would check my VST Connections I/O, and also the track’s output at the upper left 1st