You can't download Avid Liquid because the application is not available anymore. The official website does not list it as being available. According to the information on the official website, the product has reached end of life.
"Avid has discontinued the Liquid/Liquid Pro/ Liquid Chrome SE product line. As a result, there will be no further sales or development of the Avid Liquid family after March 3, 2010." - Avid website.