One additional thing that might be worth trying -

The embed call on the first two clips both indicate a "shockwave flash" program. Flash was bought out by Adobe about a year ago, and significant changes and updates were made to the program, including patches for known malware vulnerabilities that Macromedia had failed to patch for many months prior to the change. I don't know whether the shockwave application was part of that acquisition, but both are now Adobe products.

It's possible that an update to the latest versions might help. Both are free downloads at Adobe. (Look at the top right at the link.) Each of these two players will be a 1+ or 2+ MB download. You can update your Adobe pdf Reader at the same place, but the latest version of it is just over 22 MB so it's not a "trivial" download with dialup.

The "problem" described is exactly what we got with the dialup connection we had until a month or so ago, and the only remedy we found was, as suggested, to let the YouTube files download completely and then replay from the file in Temp memory. With our old connection, which appeared to be even slower than the average dialup, none of the YouTube clips could be played "first time" except as intermittent bits and pieces, so we almost never bothered trying to visit YouTube. Our new faster connection eliminated any problems there.

John