That means CATIA is not finding those parts, they are not in your Search Order...if you click on Desk command you will see them most probably being black.
You can load them by searching manually on network or modify the Search Order to include those paths...there is here on forum a thread where is explained how Search Order is working (if I remember correctly Derek explains in short words everything).
But it seems your Product Structure is OK, everything is loaded ? If yes, then you have some "ghost" links, you can run a CATDUAV to try to "clean" them.
All the parts are loaded.
On the Desk command, everything looks good: no black or red warning files!
My engineer looks anxious about the message that makes the subject of this thread....
Is his concern legitimated or we should ignore it?
On Desk window, right mouse click CATProduct and go to CATDUAV5... then in the new window check in the right bottom corner the "Clean" radio button and hit Run...
Save everything and open it again. See results...
I suggest you to make first a back-up for all your files.