Reply to My entire Traktor Library corrupted!?

Ahh, i've just opened up traktor and was about to have a mix, and i tried to load a track, and I got the red warning message

"warning bla bla bla track could NOT be played dude to a missing or a corrupt file, unsupported format or DRM-protection"....

It's doing it to every track in every playlist... Whats happened!? This has happened before but i believe i had moved all of my itunes tracks around and i ended up just having to re-import my whole library again.

I dont know why this has happened again, I can only believe of is that i recenlty backed up my itunes library to an External HD... Via, MAC>user>music> and then dragged the ITUNES folder into my external HD, but would this cause this problem? Because I can still play my itunes music without problems..

Do I need to go and clear/empty all of my Traktor playlist's and then import them all back into traktor again... or should i go though every track in each Traktor playlist and just 're-locate' each track, because i just tried re-locating a track, and it found the file on my macbook and it imported again and worked..

Thanks