did you use this switch?
http://www.stewmac.com/shop/Electronics,_pickups/Components:_Switches_and_knobs/Lever-action_Pickup_Switch.html
cause everything I have heard about it say's its a piece o crap. Check for loose connections, especially at the solder points for positions 1, 3, and 5. tug firmly (not hard) on them also if they are not loose because you may have a broken wire inside the solder connection (This has happened to me before). Check and see if any wires are grounding or partially grounding themselves. Also, don't be nervous as this is unlikely but still possible, if you overheated the switch it may not work properly, but again this is unlikely as you said it works on 2 and 4. Please do post pictures.