If no registration is required, could you give a link to a sample page that gives you this problem?

Do you see a black rectangle where the video should be, or an error message there, or is the player completely missing?

Firefox may display a "Lego"-like icon in the address bar on pages that use plugins (such as Java, Flash, etc.). Does the icon appear for that page and, if so, when you click it, does the drop-down indicate any problem?

http://www.creativelive.com/live4

No registration required. I do see a black rectangle where the video should be and I get the red "live" square on the bottom right and the "best" signifying the quality of the video and that's as far as it gets.

I have the lego icon and when I click on it it signifies that I have enabled flash (using noscript).

I have enabled javascript in Firefox in about:config. It is really a mystery to me because I had absolutely no problem viewing videos on creativeLive in the past. I am up to date on flash and everything else according to Secunia. No problem at all on other sites. Something changed and I have no idea what it was. This occurs on all three browsers - ie, Chrome, and Firefox. I use Firefox all the time, but tried the others with the same problem. CreativeLive can offer no suggestions. I appreciate your taking the time to reply.

If you pop the Ustream page out into a separate window, does that make any difference? Here is how you can do that.

(1) Copy the following script (it's all one line):

window.open(document.getElementById("live_player_iframe").src, "_blank");

(2) While on the page you linked above, open the Web Console by pressing Ctrl+Shift+k

(3) Next to the caret (">") paste the script and press Enter to run it; if Firefox blocks the popup, use the Allow button to launch the window (last option on the little Allow menu.

Does the stream play?

If not, do any other live streams play on Ustream, such as: http://www.ustream.tv/opensea

Well, that was a really interesting exercise. I love computers-- they are magic (even if dangerous magic sometimes) even though I know so little about them -- anyway, I did as instructed and was unable to view the creativeLive video or the Ustream video you linked to... although if I google ustream and go directly to their website from there, I am able to view the videos offered there -- at least that great North Face commercial -- if I tried to view anything else, they had some kind of add-on required so I didn't go any further. But the North Face commercial video played just fine.

Hmmm, if you right-click the blank area where the Ustream video should be, do you get short menu with Settings, Global Settings, and About Flash? Click Settings and make sure you allow Ustream to store data. This probably is used for tracking, but may be worth it if necessary to make the videos play.

I'll try that when the broadcast starts today at noon. I am thinking that it is the way I have my router set up -- I have it set up so that when the ports are probed, it shows as operating in stealth mode. It is very locked down. UStream is the first problem I have run into using that configuration -- except ftp and I have to temporarily change the router settings to allow that when I need it. The only change I can think of which I may have made between time I was able to view and now is IPSEC-ALG.

Do you know which protocol/ports Ustream would require that are different from most videos? Maybe I could set up port triggering for those ports or temporarily enable whatever it needs to view those videos?

As an afterthought, I realize that now I am asking you for advice that is not specifically about firefox, so please feel free to demur.

Found this info in ustream's help (for anyone else having trouble viewing their videos):

https://ustream.zendesk.com/entries/21119702-Opening-Firewall-Ports-for-Ustream-Broadcasting-and-Viewing

Will have to see if I can configure my router.

jscher... thank you for your help. Much appreciated.

I'm glad you found the help page because I wasn't going to be able to answer that one.