sage -i fails to find optional package database_gap

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running ./sage -optional and then ./sage -i database_gap-4.4.12.pl.spkg using sage -i as per README instructions (which is not recognized) or ./sage -i database_gap-4.4.12.pl.spkg, with or without extension .spkg produces the same message: *Unable to download database_gap-4.4.12.pl *Please see http://www.sagemath.org//packages for a list of valid *packages or check the package name.

The package exists so I should be able to download it and install using wget or Firefox. The question is: Is this advisable; is this package separate from Sage and can be called by sage, or do I need to use sage -i to integrate it?