yeh this is file location shit! One thing i learnt very early with traktor is too make that once you put songs in the library, never move them! for example draggin a track off your desktop, then moving it will piss you off no end.. half my library doesnt work after rearranging all my songs lol! i have a 6 copies of some tunes haha!
just can't hold myself back and have to say this. sorry, i don't want to be spiteful, but....:
this is one of the main reason why i got rid of traktor. headfuck. danwell, you're gonna have a quite a bit of these kinds of problems, i'm pretty sure of it. anyways, have you done consistency check and is your track collection analyzed n shit? sometimes it worked if i just restarted traktor and it's soundcard interface and/or op system when had problems.