You can run two copies on the same host.
However, as web wiz forums uses application variables, if the two
forums are running on the same domain sharing application variables,
then you will need to disable the use of application variables by
editing the common.asp file and also turn off active users features
from the admin area.
If you are running the two forums in different domains or sub domains
they should have their own application level variables so you won't
need to do this.
If you change the name and location of the database you simply need to
follow the install instructions on how to change the path and name
reference in the common.asp files:-
http://www.webwiz.net/web_wiz_forums/docs_access_move_ db.asp