This cable is capable of carrying audio when HDMI signalling is used. Some devices are only able to pass or receive DVI signals through their DVI ports. If this cable is used with a devices that is limited to DVI signalling, no audio will be present. This is a limitation of DVI and DVi devices, and does not indicate a faulty cable.
In such a case, audio will need to be passed through an addition a audio-only cable, or one of the devices may need to be replaced or upgraded. For example, some older PC video cards may not pass audio through their DVI port. Upgrading the video card should allow the PC to pass audio through this cable.