Reply To: Theme installation on my website

Hello,

In most cases, it happens when you have some problems with PHP uploads limits on your server. Read this article about the issue http://www.wpbeginner.com/wp-tutorials/how-to-fix-are-you-sure-you-want-to-do-this-error-in-wordpress/
We suggest you to contact your hosting providers and increase your uploads limits also.

Kind Regards
Xtemos