 That's weird, I did a fresh install on a Dell few days ago (also SATA SSD), no problem.
 I chose "Erase disk" as, in my experience, is the most straightforward way (re @lubuntu_bot: (irc) <dididi> hi im installing lubuntu on a sata ssd in a dell laptop and no matter how i select or partition the  intaller doesn't allow the next button ?)
 But I understand it's not always an option for all users