Itunes Naming All Files The Name Of First File.....

Ok here's my situation.

I just bought a Ipod Classic 160GB Ipod. I downloaded Itunes. I created a playlist in Itunes under my Ipod. Now I drag and drop multiple files into this playlist and I can't figure out why, but Itunes names them all the same as the first file. I'll give you an example.

I try and put all 13 episodes of the first season of King of the hill on my ipod. I highlight them all and drag them to this playlist, their names are like s1e01, s1e02, s1e03 and so on (on my computer that is), now when i drag say s1e01 thru s1e13 and drag them to the playlist so that it syncs them to my ipod i have 13 files named 's1e01_NEW' .

It is very frustrating, now can go and one by one rename them once they are on the ipod but that is so time consuming and I am trying to fill this ipod up with content and it's already time consuming enuf converting all my dvd's and avi's to the mp4 format, but anyway anyone got any ideas how I fix this ?