I've attached 3 solid color backgrounds to this post that can be downloaded and used in AudioLabel. Once the backgrounds are downloaded, you can use the "Insert" button in AudioLabel to add the backgrounds to your label. You can stretch the backgrounds to any size after the "Unlock Aspect Ratio" option has been set on the "Properties" toolbar. Also, you can change the "Hue", "Saturation" and "Lightness" options to get almost any color background.
Please let me know if you need further assistance.