Hi there, This issue has come up a few times with themes that have a large file size. If you do have zip installed on your server and haven't had this problem with other add-ons before, the usual culprits are a 5.3.x version of concrete5 or PHP version 5.2.

If you are running a 5.3.x version of concrete5, the problem should go away after an
upgrade. If you've got PHP 5.2 running, there's a known issue with unpacking large zip files in PHP 5.2 erroring out after reaching a certain size.

Both situations should be solved by downloading and installing the theme manually or upgrading concrete5 or PHP. Here are the instructions for manually installing the theme:http://www.concrete5.org/documentation/how-tos/editors/download-man...