Hi! Error -1603 is a general Windows Installer (MSI) failure, so it doesn’t automatically mean the disc is bad, it happens when the installer can’t write to a folder/TEMP, doesn’t have the right permissions, or a security/previous install is blocking it.
Start by right-clicking Setup.exe > Run as administrator, make sure you have full permissions on the install folder, and temporarily disable third-party antivirus/“controlled folder access” while installing.
To tell if it’s a disc/drive problem, try copying the whole DVD to a folder on your PC, if the copy fails or throws read/CRC errors, it points to media/drive. If the copy succeeds, run the installer from the copied folder and install the legacy DirectX End-User Runtimes