When laying out UV's for any object that "wraps around" (meaning one edge leaves off at one place and begins elsewhere on a seperate piece), it may occur that one of the pieces is turned the wrong way, or you may have the wrong edges alltogether.

One thing to do to check this is to go into edge-selection mode (right-click, and choose edges), select the edge you want to sew in your UV texture window, then go to your perspective view, and press "f". This will frame the edge you have selected. Now de-select it, and re-select it (in the perspective view), and go back into your UV texture window, and press "f" again. This will frame your view between where-ever the two edges that you are trying to sew.

This should show what two edges you should be trying to sew together.

If it turns out that you have the correct two edges, then I'm stuck :p