@soulpure1 You’ll find a lot more answers/solutions in Shotcut’s forum than on Reddit.
The reason why you’re getting that dialog box is because you moved the files since you have saved the project. Shotcut doesn’t know where you moved the files, therefore you need to tell Shotcut where to find them. Perhaps you had them on a thumb drive and just simply need to reinsert the thumb drive.
Instead of retyping everything, might want to read this.