Alex,
Welcome to posting on SCN!
Unfortunately, this is a very basic question, frequently asked, frequently answered (SAP Search). That search brings up 339 hits, and the top four are exactly this question. I'd like to direct your attention to the Getting Started with SCN space, the The SCN Rules of Engagement (point 3, search before you post), and Asking Good Questions in the SCN Discussion Spaces will help you get Good Answers.
Bottom line, just as Willi said: it depends. It's technically possible. It's usually a bad idea. Assuming by NetWeaver 7.04 you mean NetWeaver 7.4, STMS will stop the import unless you set a bypass option. It requires thorough and careful examination of the objects in the transport before deciding that it's ok.
Cheers,
Matt