It depends on what you like... if you want it to be accessable from yoursite.tld/ubbthreads.php then you install the files to your web root; if you want it as yoursite.tld/forums/ubbthreads.php then you'd install it to a "forums" directory.

As for your error, I get a blank page when accessing:
http://server2.termpro.com/forums/ubbthreads.php

I am a Web Development Contractor, I do not work for UBBCentral. I have provided free User to User Support since the beginning of these support forums.
Do you need Forum Install or Upgrade Services?
Forums: A Gardeners Forum
UBB.threads: UBBWiki, UBB Styles, UBB.Sitemaps
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