All kinds of suggestions now committed. Note all the errors in the command line and how you get feedback:

1. Nonexistent driver (type in driver name). You get the same error if you typed it correctly but the driver cannot load for whatever reason:

       $ perl ./geoip --no-fetch --DB=dbi:SQXLite:dbname=geoip.db
       Cannot continue without a working database
       Did you forget to install DBD::SQXLite?
   [download]

2. The dbx: part won't ever find a (standard) driver, so

    $ perl ./geoip --no-fetch -DB=dbx:SQLite:dbname=geoip.db
    Cannot continue without a working database
    Maybe the matching DBD for dbx:SQLite:dbname=geoip.db is not insta
+lled
[download]

I also made a few adjustments to the documentation based on marto's feedback. Thank you!

(FWIW I have no idea what the errors will be if the machine does not have enough memory to create the database)

Note that if you fetch new data files, you will need the memory again to load/update the database.

For normal operation (--no-fetch) you don't need that much memory.