Why cat you be nicer? He made a mistake, is all. I mean, the 'n' key is pretty close to the 't' key... :biggrin:
As for the OP, no, you can't gain perks after hitting level 30.
However...
Spoiler There is a way to gain up to 28 perks in a single playthrough. It's somewhat complicated and takes a LOT of time and patience.
http://www.gamesas.com/index.php?/topic/1141992-28-perks/