I have the same problem, It started several months ago, It worked at one time but I guess PB changed something. And I have not figured out how to get it to work.
I’m able to capture the URL, download and play the flv files with a 64-bit openSUSE-11.2 Linux on KDE-4.3.1, but they did not play in my Firefox browser:
MozillaFirefox-branding-openSUSE-3.5-8.9.1.x86_64
MozillaFirefox-3.5.5-3.1.x86_64
flash-player-10.0.32.18-3.2.1.i586
pullin-flash-player-11.2.1-0.1.1.x86_64
mplayerplug-in-3.55+cvs20090923-0.pm.2.1.x86_64
Where firefox has Video Download Helper installed.
Its possible by tuning a User Agent setting, one could get the videos to stream properly.