Error: num_rows() on a non-object

[eluser]ThaMy[/eluser]
[quote author="rogierb" date="1254421170"]Your database setting are not correct. Check them, then double check them:-) The rerror will go away once CI can connect.

Leave the db_debug to true while you are in development.
If you have a problem with either the database or a query, you will notice imediately.

Edit: The error is probably not related to redux.[/quote]

I checked the setting to my database and it is ok, but if I leave db_debug to false, I cant connect.

This application was working in another server, I'm just migrating the server and the domain

Any idea?