I made camera motion for the song used in Nyan Cat that everyone seems to be all over ("Nyanyanyanyanyanyanya!") in MMD

I was trying to figure out why it wouldn't let me render to an AVI file until I looked at my screen size.
Somehow, I'd gotten it to "1600x1200" when I'm on my sister's computer with a "1024 x 768" screen resolution.
I don't even know how I'd managed to get it like that when usually it stops me from putting it over.

So I guess it won't let you render if it's over. You learn something new everyday!
Have any mistakes that you had no idea would affect MMD happen to you lately? How long did it take you to figure out what you did wrong?