If I open just one of this sites, the video show fine, but after opening a second or third most of the time the error "Error loading playlist: Error loading file" is throw.
This situation was found on Chrome, IE looks fine, mozilla not tested.
Hello,
maybe it's jwplayer bug, The 6.11 will be released soon, in meantime I can send you a beta version with this jwplayer version if you are interest.