Your normals are reversed on one piece of the geometry.
I'm not sure what version of Maya you are using so If you are using Maya 8 or later then go to Display at the top of the UI and in the Polygons submenu set click on face normal, this will display a green line in the center of the faces telling you which way the normals are facing.You want the normals to be facing the same way as each other which should be out from the geometry, look for the faces you think are the reversed from the majority and select those faces (to turn the normals back off just click on face normals again).Now go to Normals at the top of the UI and click on reverse,you should now be able to perform your bridge.
In earlier versions of Maya the path to display normals is Display / polygon components /normals and the command to reverse the normals could be found under Edit Polygons/Normals.
Some users might just select all of the geometry and go to Normals and click on set to face which can work but doesn't always.
2 x Modeling Challenge Winner
Last edited by jsprogg; 23-09-2007 at 02:52 PM.