In the last example, "one_source_html5" and "one_source_flash" played perfectly in IE. This suggest that the problem is not flash, instead is multiple sources. this also explains why videos on your main site play fine on our IE
The problem with this set up is that it does not play properly in firefox video is downloaded when played).
You documentation does not make it very clear if in order to use 'sources:' one HAS to use bc.. "playlist: [{ }" , But I tried anyway to no avail.
Do you have a Setup Wizard that can set up multiple sources? could you please take a look at my mark up and tell me if I made some kind of mistake?
maybe IE8 was once used in compatibility mode (the toggle right beside the URL text field) and kept this setting for this URL?
This could be an explanation, because in normal IE 8 mode (i.e. not compatibility mode to IE7) Player 6 works for me, but for IE7 (and also IE >= 8 in compatibility mode) there is a know issue which longtail will fix with player 6.1, as far as they sad.
So maybe you should check if after cleaning all temporary data (not only cache but all offline data) the problem still is there.
I see what you both mentioned before: When I toggled compatibility mode the videos DID load. The problem was that compatibility-mode appears to be enabled on page load with IE8 - which we tested on various PCs. A very large part of our demographic is made up of IE users. Doubt they would know what to do if faced with this problem. Just a note in case this really is a bug to be fixed.
This morning I tried two other things: Removed extra comma from bc.. .webm" , } that I had not previously not noticed.
Made sure that video ID's in html used double quotes and video ID's in Javascript used single quotes.
Not sure if one or a combination of these did the trick but getting oppressive test on all desired browsers! :)
Here is my final markup in case someone else runs into this issue: