FCPX Project won't Share without "Video rendering error"

I re-installed the OS (mojave) for my Late 2013 macbook pro, installed/updated FCPX and when I attempt to share a video project, I get a share operation error.

"The Share operation failed" Video rendering error: 10008 (The operation couldn’t be completed. Error processing frame, 100GreatestGuitarIntros @ 00:12:47;40 <<Error in render file, /Users/tayst/Movies/MyMovie.fcpbundle/.fcpcache/3-28-18/Render Files/High Quality Media/E0E9450F06C20FDEA235A8F266AB4AA6 @ # 245>>)

There was an advise that when I started the Share operation, there was some missing transitions, et al, that they would be replaced but I was OK with that (I can't find them).

See two attached screenshots.

I'd like to know how this can be fixed.

thank you