Hi Charlene. 
Any object you add into your project needs to be saved in a single folder onto you computer, in C: if possible. As you stated above, you can not moove the objects you have added into your program or else the program will not find them anymore. Please add them in a folder in C: then link them to your project in order to avoid problems.

Thank you!

I didn't realize that, so they are in various folders in my computer. Not all in one place. Is there no way to "embed" them permanently? Is there an easy fix for this?

You can keep them where they are as long as you do not move them. As I said above, the best thing to do, in order to avoid problems is to keep them all in c:. Once you have exported your project you won't have problems anymore.