I'm trying to install PhPbb boards, and I have NO clue what to put in the section that says DNS/Database Server Hostname...what am I supposed to put there?! Help PLEASE!!!

I believe that will usually be localhost but if that doesn't work, you will have to ask your host :)

i'm gonna agree with Dude128. use localhost normally, but if you connect remotely (e.g. http://freesql.org) you will ask the host