Just curious when importing an object (say a weapon) and then exporting it into NIF why would I get this message ? Unable to open the specified NIF file : Version to old ... Please try again. I downloaded everything I could find is there another plugin that Im missing ? Or is it not possible

You have to config your export script. It's explained in the 2nd post of C.Rolands tutorial:

http://forums.civfanatics.com/showthread.php?t=167335