Hi Lish. It seems you have at least one surface which is folding back onto itself. Perhaps it will join up as a closed polysurface, but this will be a problem if you try to run a fillet or chamfer. Also it may create very heavy mesh when you export. I am guessing you made that surface using Network or Sweep with 2 rails? This can create problems when making a 3 sided surface . I would suggest you create a new 4-sided surface which extends beyond those edges and then trim away the excess. That is best way to avoid folding near a singularity...

jonah