When you upgraded your Firefox to version 4 on your 64-bit Ubuntu as per this tutorial, you may find that the flash is operating abnormally. Now, we can fix this by installing the latest Flash from PPA.
HOWTO : Latest Adobe Flash for 64-bit Ubuntu 10.10
Archived thread 1719080 from Hong Kong Team. Markdown source: Hong_Kong_Team/thread_1719080_HOWTO__Latest_Adobe_Flash_for_64-bit_Ubuntu_10.10.md