FCPX Export Issue

Newbie to the community, looking for some help!

I have been working on a 50 minute video of a live musical performance There are 9 songs each with their different Multicam clips, Compound Clips, Effects and Titles which I made 9 separate Events for, while working on them individually. I have combined all 9 songs onto 1 Timeline so as they flow from one to the other and added the final touches. I also made the the whole musical performance into 1 Compound Clip. I cannot, for the life of me, get it to Export.

I keep getting error message: "this item cannot be shared while it is still referencing media on the camera."

I've already tried the whole 'Import>Reimport from Camera/Archive' and also the 'Relink Files' things but to no avail. The little camera icon in the Clips does not show that it is reimporting, like it does on some of the tutorials I have seen online (while everything is still plugged in). The little camera icon stays. I've tried reimporting my content from my Canon camcorder, and my Nikon SD card directly onto my desktop, and then drag it into FCPX, but it still won't work. My SD card seems to be the problem as I remove it, I get the "Missing File" messages where those clips should be, and when I put it back it, the Clips reappear. Even when I upload either from my desktop or directly in FCPX, as soon as I remove my SD card, the files go missing.

Am I missing something here? Any help is appreciated. Thanks!

Frustrated.