I posted this question to the "Getting Started" forum but got no response after several days so I thought I'd try here.  I also tried Telerik but they said they don't support  the RADEditor that ships with DNN. 

I've inserted a video with the RADEditor Media Manager.  The video plays fine when one computer accesses the site and not at all when another computer accesses the site. Looking at the Properties of the Windows Media Player that got inserted into the pane  I can see that the Location variable for the video on the computer that plays the video is correctly displayed as

                                                      http://www.steveswebshopsandbox.com/Portals/10/scan_ed.wmv

But Location on the computer that won't play the video  it is incorrectly displayed as

                                                     http://Portals/10/scan_ed.wmv

Clearly the second Location isn't going to work, but why in the world would one computer pick up the correct absolute address and another computer pick up an incorrect relative address? 

I notice that the Media Manager inserts a relative address into the HTML:

                                                         <param name="URL" value="Portals/10/scan.wmv"

So it seems to be relying on something else to build the absolute address, and that something isn't always doing the job. 

It seems like the Media Manager should always write the absolute address into the HTML and, in fact, this is how I've worked around the problem, by going back in and editing the HTML that the Media Manager generates.  So if I change

                                                                      <param name="URL" value="Portals/10/scan.wmv"

to

                                        <param name="URL" value="http://www.steveswebshopsandbox.com/Portals/10/scan.wmv"

the video plays  from all computers.

Does anyone know what's going on here?

Thanks,
Steve A