I recently installed Sugar CRM CE 6.5 on a clients dedicated server only to be greeted by the infamous WSOD.
Apparently this is a common issue with Sugar CRM but unfortunately this was a special case so none of my google searches yielded a solution for my conundrum.
Which is why I am posting this here :)
My clients server is running php under mod_suphp so this post was helpful in solving some sugarcrm permissions issues when running under this configuration.
http://ma.juii.net/blog/install-sugarcrm-ce5-5-with-mod-suphp. The important bits being: