Flash Player for Linux

Hello,
i have a little problem with my Flash Player.
I am running the latest Ubuntu with the latest Firefox.
When i go to Websites like Youtube with a lot of flash content my Firefox locks up.
Do you think this is a Flash or Firefox problem?
A soultion for this would be very nice!

Regards

Jan Payman Ameli
JPA-Software
http://www.jpa-software.de