Welcome in the forum, Luke.
Attached is a project archive of the bootloader project, expand it to a directory* of your choice and compile it.
Open your LED_ON_OFF project and remove the bootloader project.
Set the properties of the Bootloader component to point to your newly generated .hex and .elf files (Buried deep within your directory*)
Happy coding (and remember the force)
Thank you for the welcome, and thank you for the help. I think the issue was with the file path length. After moving the UART_Bootloader project to a higher (shorter named) directory, I was able to compile the hex files, which I selected for my Bootloader component. It then built correctly.
Thanks for the advice,