They are related to LabelPro. Projects created using LabelPro can be opened through Avery DesignPro. Download the latest version of the software from:
http://www.avery.com/avery/en_us/Se.... To open an existing project: Go to File - > Open - > from the File Type drop down menu select "LabelPro 2.0 -3.0". If the file was saved correctly you will be able to open it and perform any necessary edits.