SQL Server 7 create DB error

Hi, i'm using the CREATE DATABASE xxx on (filename='...') for attach
using two .mdf and .ldf backup files.
But i'm having the followin error:
Database 'xxx' cannot be opened because some of the files could not be
activated.
What is it? Are the files corrupted?
If so... is there a way to restore them? The .mdf file is 500Mb but it
doesn't has more than 5-8 Mb of data. So, are there tools to restore the
information?
Thanks a lot

--
Guillermo Casta?o Acevedo
Gerente de Sistemas - Grupo Millennium Ltda
Guiller...@GrupoMillennium.com
www.GrupoMillennium.com
Quid quid latine dictum sit, altum viditur