[arch-general] database non-existent error

[message]

Readers,

A little history: previously a mandrake and suse user,just tried mageia 
that failed and now want to try a different system!

Version 20140301dual was downloaded as an iso file then burnt onto a CD. 
(This was a reason to try: other distributions are getting too big, 
beyond the typical cd capacity).

The (old) pc file structure is inherited from mandriva, with separate 
mount points for m$, /home /swap /boot /.

Tried the command:

pacman /mnt base

error response, that database files are non-existent for core, extra, 
community.

What to do please?