I've been to the strip before but now when i try to go in it says that it requires a key. Also it sounds like the security bots are barking. I have a passport and 10,000 caps.

Any ideas why I can't get in?

No idea. I have the same problem.

I had the problem and eventually took the monorail from Fort McCarran into the Strip. Then the gate was unlocked again after that.

Ive tried it but the quest "I Put a Spell on You" is bugged for me, meaning that no matter what I do everytime I zone in to the monorail from Fort McCarran it explodes.

Same thing happened to me. Hopefully you're a PC user so you can use the "unlock" console command. Otherwise, monorail is your best bet.

It is possible to become locked out of The Strip's main gate. The prerequisite actions may be taken, but the door will remain locked, requiring an unobtainable key. entering in the Strip from the monorail seem to unlock it.

Taken from th wiki.

Man, you're friggin' kidding me. Not to make a big deal, but my wife is playing on the xbox and just encountered this bug and is now crying from all of the investment she's lost. Literally, this issue has done of the opposite of create the joy and entertainment product is intended to create.

Wow. Pretty unforgivable.

Wow, I feel bad for you guys. I walked up the first time to the gate of the strip, and I used my option that appeared with 80 science. That's it. Got in 2 seconds later. Have 1000 caps on you, you don't have to pay it.

Getting in the first time isn't the problem. It seems like all these people, including myself, have already been to the strip. For some reason the gates have become locked and a key is now required. I don't know how many people here play it on the computer but I play on the 360, so it's yet another problem with the game itself. This didn't happen my first play through but now on my second character it has. This is extremely frustrating and I sincerely hope someone from Bethesda or Obsidian reads this so maybe the next time they put out a game they spend a little more time actually play testing the damn game. Also, it's 2,000 caps to get in the first time=)