Unable to Sign In to iTunes from apple tv (1st Gen). GRRRRR!!!!

Question

Two days ago I was searching for movies to rent. So I casually went on to the Apple TV to browse all the HD movies. The #1 movie was Iron Man 2 (I watched the preview), #2 was Get Him to The Greek. I decided to opt for the comedy and rented Get Him to The Greek right from my Apple TV. I watched it and all was right with the world.
The next night I decided that I'd rent Iron Man 2 (wife's out of town). So I go into the Apple TV to get it since I knew that it was the #1 top rental the previous night was Iron Man 2. Much to my surprise, Iron Man 2 was nowhere to be found in the iTunes store on the Apple TV. Not further down the top rentals list. Not in the alphabetical listing of all movies, not even in the search. "Well that's bizarre," I said to myself. "I wonder if I can find it in the regular iTunes store on my Mac Pro?" Well sure enough, iRon Man 2 was there. So I rented it on the Mac Pro. Curiously, it didn't show up on my Apple TV. I waited and waited. So I went back to iTunes and, oh silly me, I have to put it there in the iTunes sync dialog and then sync the Apple TV. I did that, and since it was late, I went to bed.
Today, I finally got the kids to bed and cleaned up and decided to watch my rented Iron Man 2. Fire up the Apple TV, see that Iron Man 2 is right there at the front of the listed movies on my Apple TV. Sweet. Select, select play, settle in with a nice drink and ....
Your Apple TV is not authorized to play this content.
What the?!?!
Hrm. That's weird. Well let me double check that I can play Toy Story (a movie I had downloaded and watched with my boy a while back). Yup, Toy Story works all right. So I decided to futz around a bit to see if I could figure out *** is wrong. Over to the settings list, hmm, maybe I should try the "Downloads" option? Click. Okay it says "Check for Downloads." Sure why not. Click. Enter your Apple ID. Yeah okay. Now enter your password. Done. And...
Unable to Sign In.
The Apple ID you entered couldn't be found or your password was incorrect. Please try again.
What? Oh silly me, I must have made a mistake and entered the wrong email address or password. I'll just do it again, I'm sure it'll work this time. And...
Unable to Sign In.
The Apple ID you entered couldn't be found or your password was incorrect. Please try again.
Um. Okay, third time's the charm. First let's go into iTunes on my Mac to make sure that I really am entering the right information. Yup, exactly what I thought I entered on the Apple TV. So back to the Apple TV to enter the username (and triple checking it) and the password (carefully inspecting each character as I do it). Still no luck.
Well I guess I'll look up this error online. I found an Apple Support document that indicates there is a problem with aol.com email addresses to log onto iTunes from the Apple TV. That shouldn't be it, I'm using a gmail.com address. Then I found an Apple Discussions link from 2008 where people were flustered by this issue. A few had gotten their Apple TVs to work again by unplugging the Apple TV and deauthorizing and reauthorizing the computer the Apple TV is sync'd to, plugging the apple TV back in and syncing the Apple TV back to the computer.
I gave that the old college try. I came back to try the Apple TV and still got that Iron Man 2 was not authorized on the Apple TV. I thought I'd try Toy Story just to make sure that it still worked. Now that movie said the Apple TV was not authorized to play that movie.
I'm going backwards! Things that were working now aren't and I've spent my entire night trying to figure this crap out. Someone please help me make this "just work" so I don't have to go and smash it to pieces with a baseball bat. My stats as of right now:
1) I can't log into my iTunes account from anywhere it asks for it on the Apple TV. I've tried settings>downloads, settings>general>itunes store, settings>general>network>test network.
2) I can't log into my YouTube account. I've triple checked that my information is correct.
3) I can't play any movies purchased through iTunes even if they were purchased from my Apple TV.
4) I CAN play music and a music video that I purchased on my Apple TV and music I purchased from my Mac.
5) I can play a TV season that I purchased some time ago on the Apple TV.
6) I can log into my account in iTunes from both of my Macs.
Oh also to get the easy questions out of the way: 1) Yes I'm 100% certain that I entered my username and password correctly. 2) I am completely up to date with my iTunes software on the Mac and my Apple TV software (as far as I can tell).
I'm trying to stay calm and keep things light. But holy crap this is frustrating. I spent good money on the movies that I can't watch. I wasted hours and hours of my time troubleshooting and researching only to find myself going backwards and losing the ability to play things that I once had no problems playing. This just isn't working and I wasted my whole night on it. Someone please help!

Answer 1

I cannot help you other than to say I have exactly the same problem and have been trying to resolve it for over an hour now with no luck.
Besides unplugging and replugging in my ATV I have also tried:
- resetting my password to the same thing
- resetting my password to something else
- creating a new Apple ID and trying to use it
None of this works.
At this point I am guessing that Apple's servers are hosed and the error message is just incorrect. Hopefully they will fix the problem at their end over the weekend.
And yes. Holy crap this is frustrating is putting it mildly.
It amazes me that just a few hours ago I was playing with FaceTime and thinking very positively of Apple, but now I'm just ****** at what is clearly a screw up on their part.