Not able to listen to the sound-file for lessons

This may be just a weird glitch that will go away when I try again tomorrow, but I have not been able to listen to the sound for any lessons, including ones I have played only yesterday. I have not got a cable in the sound output socket, nor do I have the sound turned right down. The numbers with the time of the sound file do not appear at all. I can listen to podcasts and previously saved files on iTunes on the same computer, just not hear files on LingQ lessons.

@Ginkgo58 - Would you be able to let us know which browser you are using? Also, is this an issue in other browsers as well?