go to system> administration> synaptic package manager. type in your password if needed. in "quick search" at the top type in "flashplugin-nonfree" and check the box when it shows up in the list. several other plug-ins will be installed with it. then at the top click "apply"

are you running noscript on firefox or anything that could be disabling javascript? i've never had any problems with flashplayer after installing it from the synaptics manager. check for firefox updates, also try another website like Hula and see if it works there. try reinstalling the flash plug ins. signing up for the ubuntu forums is an excellent way to learn a lot of the tricks to run ubuntu.