Due to the fact that I can't tell if you have made any changes to your 
Informix server let alone what the password is for it you will have
to configure the Informix server by hand.

There is a file called ifmx_create.sql in imp/lib/scripts that all you
have to do is import that into your Informix database.

If you make changes to the name of the database, 
the manager name or password, you will need to make
the same changes to your config/defaults.php3 file as well.

In other words, make sure your database names match what's in
imp/config/defaults.php3

