I reassembled a Glock 23 incorrectly -- it was my first try at installing a new Ghost trigger bar kit -- and didn't hold my mouth right. I went to the Glock Talk site (in their Gunsmithing area) and got a lot of quick, to the point, advice from folks who know those guns inside out. They diagnosed my problem and had the gun right quickly.
Little things like reinstalling the pins in the wrong order will cause all sorts of functional issues.
Try them --
http://glocktalk.com/forums/forumdisplay.php?f=23