Problems with pin connection

Hi, I'm working in ProE (wildfire 3) on a model of a glider. I started with an assembly and made all basic parts there. Now I wanted to move into more details so I opened the wing part and made a cut for aileron and also saved this cut as separate part. Now when I try to put this part (aileron) into assembly and connect it to the wing with pin connection I get an error "selected axis in first constrain is in the ground body" and connection cannot be established. How can I solve this problem? Is my approach wrong (working in assembly then modifying and saving new part and putting it back to assembly?). Thanks in advance for any help.
Mike

The interesting thing about the Master Model approach to assembly modelling is that every part you create is fixed to a default coordinate system. It's bricked in place. Locked in concrete. No movement permitted there. So, what I'm thinking is that you must do the parts differently, not with default constraints, not with offset to a csys (the kiss of death to motion). Maybe you need to set up something else than the defult csys, maybe some points, planes and axes!?! I don't really know as I'm not looking over your shoulder. But, I do know that the Master Model approach's got you by the balls. Breaking free will require deeper investigation into this approach.
David Janes
  Quoted Text Here  

I've found it useful to create a new assembly for mechanisms. Don't create any new features in the new assembly, and keep it only for merchanisms. It has worked well for me in the past. this way all your features can be made to line up, and master model methodolgy can still be used.
Cheers Craig
David Janes wrote:
  Quoted Text Here