can't get past a certain point when adding music.

I recently got a 80gb Ipod classic. I can get about 7gb of music on before it just stops loading. I use copy trans manager because most of my isn't on my Itunes. I have windows vista on my laptop. My music is on an extrenal hd. I know the problem is not the hd and Ipod sharing the same drive letter.
Here are the hd specs.
Retracts: 1453
Reallocs: 414
Pending Sectors: 13
PowerOn Hours: 3175
Start/Stops: 677
Temp: 28c
Temp: Min 1c
Temp: Max 50c

via iLounge Forums http://ift.tt/1QY5WD4