App Store Login Apple ID Not Found/Password Incorrect?

Question

So every time I go to install an application, I enter my password and I get this error:
"The Apple ID or AOL screen name you entered couldn't be found or
your password was incorrect. Please try again"
So I then go to iTunes on my Mac, click on "Account" in the iTunes store, and I get the exact same error. I'm 100% positive I'm entering the correct password.
I click "Forgot Password" and then reset it back to what it is EXACTLY, and everything is fine, until the next day.
The password will work on anything else (mail, apple.com login, etc.) just not anything to do with the iTunes store.
Why do I have to reset my password every day!?

Answer 1

I have been dealing with the exact same problem. Trying to access my account (in iTunes, or the myinfo site, or ESPECIALLY from the AppStore app on my 3G iPhone) results in the standard "account doesn't exist or password incorrect" error. Occasionally I get the "account disabled for security reasons" error. I assume this is because sometimes while frustratedly trying to use my account I exceed the max # of failed login attempts and Apple locks the account.
The only workaround (which is no workaround at all) is to do as you have: reset my password every few hours. I experimented with checking the interval before the password is mysteriously invalidated - it seems to be between 3-4 hours after a last successful login (I don't know if this is an absolute interval, i.e. your password is invalidated after this time period regardless of your successful login activity or if there has to be a period of inactivity to trigger the password invalidation).
I talked with phone support and after the usual reset-your-password flowchart walk-through was directed to the iTunes email support page. Typed in my problem details and 72 hours after the absolutely guaranteed reply time of 24 hours have yet to receive any reply.