hey,,i want to create a new type of weapon or armor for oblvion but which programs i need for that,??????

Blender, along with assorted plugins for working with Nifs. See http://cs.elderscrolls.com/constwiki/index.php/Installing_Blender on the TESCS Wiki. Also, NifSkope.

i already downloaded this and install thme but i can import only a few things in blender when i try to import something i got this error "RuntimeError: Unknow block type encountered during file read: BSXFlags"

OK, for one thing, please, try to use proper English spelling and grammar. Not expecting (or even wanting) Shakespeare, but capitalization and punctuation go a long way towards making your posts easier to read. This isn't instant messaging, you can take the time to spell things right, fix typos, and give your post a once-over before hitting Add Reply. We're all volunteers here, and if your posts are too hard to read a lot of people simply aren't going to bother.

Anyway, I'm afraid I don't know why you're getting that error. BSXFlags are a pretty common blocktype, I can't imagine that the Nif scripts for Blender would fail at them. Uhm, well, if no one here can answer your question (and someone might), you might try the NifTools forums.

You have two threads active, follow the answers given and you should be able to fix your problem.

i fixed it i`m now using python v3 and everthing is OK ,,thx everyone