FOX is always region locked.
Warner is not, hopefully Universal and Paramount isn't.
Get him to check the region coding (the octagon symbol) if it's says (depending on whether you got your player from)
A - United States, Canada, Japan, Hong Kong
B - Australia, UK, Europe, New Zealand
C - All the rest
so basically if you got your player from the UK (example) it is a region B player and will only play discs labelled with the B octagon sign.
Oh found out cloverfield is distributed through Paramount, most likely it will be region free but check just to be sure.
Region coding is a pain I know, I can't borrow any of my friends discs or buy discs from the shop down the street as most of them won't play! (Region code screen of death comes up)