If you are having trouble with either your audio or video not recording, you may need to check your Flash plug-in settings. These can be accessed via a control-click or right-click in black frame of the blipbomb widget.

It brings up a contextual menu that has a choice called "Settings..."

This is what the Adobe Flash Player Settings window looks like.

From this menu you can get to the audio input volume and turn it up. You can also making sure you are using the right input option within the same window.

Also you can choose the proper video input device (most likely USB for a lot of you).