This app is discontinued since 2014! If you install it, don't rate it 1 and say "Needs an update". Makes no sense. There's a free version in the link below. ZipInstaller for CWM + TWRP + 4EXT Recoveries. Root required. For discussion, free version and source code: Overview.
It's safe to download the tool. This application was originally designed by Yamil Ghazi and it is included in the Productivity category. The most recent update of ZipInstaller was launched on Feb 25, 2014 and the app was downloaded by over 1K users.