In order to install the Liquid Music and Liquid Rhythm Max for Live plugins, you must have Ableton Live 11 / 10 / 9 and Max for Live. When these components are detected the option to install the plugin is enabled in the installer and will not be greyed out.
Liquid Music 1.8.0 + Liquid Rhythm 1.8.0 use bundled Java and require no extra setup in Live 11 or Live 10; Live 9 users will need to install Max 7 (64-bit). (Liquid Music 1.8.0 + Liquid Rhythm 1.8.0 is 64-bit only). See the Liquid Music 1.8.0 System Requirements for more info.
Liquid Music 1.7.0 + Liquid Rhythm 1.7.0 (and earlier) require system Java 1.8 JDK in the same architecture as Live (64-bit or 32-bit). Live 11 users require Max 8.5.1 or greater for Liquid Music 1.7.0 Max for Live compatibility. Live 9 users will need to install Max 7 in the same architecture as Live (64-bit or 32-bit). See the Liquid Music 1.7.0 System Requirements for more info.