You can't expect to get an accurate legal advice here, but here are a few things to discuss with a lawyer (liar):
1). Can I upload movies that don't have copyright?
2). Can I show copyrighted unlicensed content to registered users only?
3). What do I need to do to purchase a licence for a movie, related to what exactly I want to show to my users? ("I want to start a movie website" is not a product definition)
4). Is the content illegal in some countries? How to write my terms and conditions?
etc.
Hope that helps.