Hello, I am here today with the following problem..

I am trying to do what is going on in this video, where parts of a gun are cut and pasted onto another gun: http://www.youtube.com/watch?v=xf_Qt_lfMxM

My problem with this, however, is that when I try to open a mesh in nifskope, I get this:
http://img203.imageshack.us/img203/7628/alienblasterdurr.jpg

All nifskope videos I've seen just have the guns with their textures pre-assigned and no orange casing. I am a complete beginner into any sort of 3D manipulation, so I don't really understand any of this, haha.

Thank you for any help you can give,

Make sure File -> Resource Files and Render -> Settings... -> Custom are pointing to your .bsa files.

Thank you, now the textures are working well, but I still have the orange box surrounding the item.. What can be done to hide that?

Under Render, untick Draw Havok.

Aha, thanks both of you, now it looks just like in the tutorial