OK, let me see if I can work out what is going on. Have you got the script to work and display the welcome bit with the login box (similar to on
my website ) If so, and the login box isn't working it may be due to the paths in the template files
Look in the webwelcome_logincode and webwelcome_logoutcode templates and make sure that the paths to member.php are correct. Because you are on a subdomain, you may need to make the paths absolute ie
http://forums.yourdomain.com/member.php etc.. You will need to do this with all the templates (I wrote them for my site and haven't gotten around to making them more generic yet). You may be able to just use $bburl/member.php instead?
You will also need to alter the cookie settings in your admin control panel so that it affects the whole domain rather than just your subdomain (see some of the earlier posts about this).
Darren.