I have been playing on New Vegas on hardcoe for the last couple of days now on the PS3 version after having been a fan of Fallout 3, with which I also experienced this serious bug. It's a game killer, if you are unfortunate to get this nasty you'll have to start over again and there is no guarantee that it won't reoccour on your next playthough.
Basically, I was going through the missions etc and all was well with the world until I leveled up at level 10. The level up music played and the screen came up as normal where you choose where to put your points in (the "lockpick, guns, melee" etc etc screen). After doing so it then goes to the screen where you can choose a perk (nothing wrong with that, it's supposed to).
NOW here's where the problem arises. I CANNOT choose a perk! The option to choose a perk is greyed out and not highlighted and CANNOT be chosen whatsoever. I had this exact bug (though it was around level 20 or so) on Fallout 3 which has obviously been out a while now, so I can't fathom as to how such a game breaking bug has filtered through into the next release.
This bug kills your savegame and all of your hard work playing/collecting/leveling up all goes down the toilet! You can reload the save and try and do something other than at the point of levelling up as last time, but when you get the level up and points/perk screen, the same thing happens. You can choose where to put your points..................but you can't select the perk. This means you can't continue in the game as it won't let you out of the points/perk screen.
As someone who paid good money for two games, both of which are broken, may I ask why such a serious bug made it to release, and why they still haven't been patched in Fallout 3 or New Vegas 1.02 to date!?