I've been looking into the error message you mentioned Helen and the only thing I have managed to find is someone else testing it as follows;
- Through my testing, I found that at times, while acquiring the embed code from the YouTube website, I missed checking the box beside the prompt: Use old embed code [?]. This is a critical error so make sure to always check that box.
- Check any other option in this section if you desire. It is not important whether any of these other options are checked. Those options are for your personal situation.
- Even if you know you had checked the box as mention above, you may still get the error message. In my case, when that happened, I tried closing all programs and starting again, acquiring the code, starting up PowerPoint and then reinserting the code. But alas, still no luck.
- The only way I had success was to close all programs and reboot my computer. What this does is erase the error message being stored in the memory of your computer, (also known as RAM). Just closing all the programs can still retain this message in RAM, so only a reboot will refresh that. After a reboot, I found in most instances, I was successful in inserting the code. Go figure.
Hope this helps