hey! someone just -rep me on this thread!
who the hell is that!?
@salahnecibi,
after add your domain(domain.com) as addon domain,
the "Document Root" is "/public_html/domain.com", right?
now install the multiforum script on your domain.com (/public_html/domain.com)
then create a subdomain "*.domain.com" and point its "Document Root" to "/public_html/domain.com"
make sure your host have mod_rewrite installed.
now, you can create forums with under the domain.com such as abc.domain.com
by the way, make sure your .htaccess under /public_html/domain.com is writable.