dashboard–>appearance–>customize, couldn't open

I want to customize the appearance, but the setting page doesn’t open as before. It’s blank when I click “dashboard–>appearance–>customize”.

It has been a while.
Is that only me or is there anyone facing the same problem?
Any ideas?

Thank you very much!

Here are 2 screenshots. Sorry it’s in Japanese but I put some English sidenote.
http://fukushilab.org/language/ja/screenshot/
Need to fix the problem and replace the images in frontpage. Someone please help.

[ No bumping please. ]