This is a windows installer error basically informing that there is not enough space on your drive for the temporary (unzipped) data folders needed for install… I suggest to clear your dustbin or download folder as some easy steps to start clearing up some room prior to install.
Indeed, my bad, 1603 is a general ‘fatal error’ message related to the Ms Installer. The fix in the above thread should address this issue for Cubase specifically. My fix addressed a separate issue (different software).