Using a "cracked" version of Virtual DJ to unlock features like CDJ-3000 skin integration is highly discouraged.
Instead of risking your hardware with a crack, consider these legitimate ways to get the CDJ-3000 look in Virtual DJ:
You don’t need a cracked CDJ-3000 Virtual DJ skin to enjoy a professional, Pioneer-style interface. Not only are cracked skins dangerous and unethical, but they’re also unnecessary. High-quality free skins exist, premium skins are affordable, and building your own is a rewarding project.
Support skin creators. Keep your computer safe. And most importantly — focus on your music, not on hacking your software.