What does a locked status mean on an inactive domain?

I was checking the whois info on a domain thats been inactive for sometime now and i wanna register it when it expires in a few months. it, however, says that the status is locked "Status: Locked". what exactly does that mean? does that mean I wont be able to register i when it expires or wut?

1- Go to: http://www.goldpuma.com

2- From "Domain" menu, click "Register a new domain"

3- Click "locking domain" !!!