That's a common issue caused by not uploading the correct zip file. Go back to http://themeforest.net/downloads and when clicking the Download button, choose the "Installable WordPress file only". This is what you should be looking for on your screen:
Articles in this section
- Troubleshooting Guide
- Missing style.css — Installation Error
- Outdated WooCommerce Templates
- Error the link you followed has expired
- How to speed up Shopkeeper?
- How to fix Blurry Thumbs?
- Error: "Are you sure you want to do this? Please try again"
- WPBakery Page Builder — How to update?
- Demo Import System Status
- Fatal error: Allowed memory size of xxxxxxxx bytes exhausted