Okay, so like many of you, I'm playing my shiny new copy of Pokemon White this week, and I (unfortunately) stumbled across a glitch in the game that forced me to shut down to get out of it.
The glitch works like this: You're down to three Pokemon when in a double battle, and both of your Pokemon on the field are knocked out at the same time. So, now you have to put out your sole remaining Pokemon to continue the battle. However, due to this glitch, you are unable to continue. Every time you try to select your remaining Pokemon and send it out, it tries to have you select a Pokemon again.
I have located a recording of this phenomena online. It's in Spanish, and with what little I can translate I cannot tell if the video names a solution. However, I'll share the link here so you can see what I am talking about. The relevant bit starts about 2 minutes into the recording.
http://wooper.forumfree.it/?t=52025934My theory is that the game has two positions to fill on your half of the field; let's call them A and B. After you select your last Pokemon for position A, it asks you to fill position B. However, filling position B leaves position A empty, creating a loop as your last Pokemon is unable to be in two places at once.
So that's it for my warning. I advise staying out of wild Pokemon double battles you don't know you can win without saving first!