Thanks for your reply.
I deactive the flashblock and access YouTube video (http://www.youtube.com/watch?v=gppbrYIcR80
Then, the following error dialog.
Adobe Flash Player 10
Error #2044: ...(some japanese message)... IOErrorEvent : text=Error #2036:
If I activate the flashblock and access the above video,
the large amount of error log is output in the Chrome console.
The error log reports that "new Image()" in the YouTube script failed.
If you know the cause, please teach me.