One set of songs is refusing to go in the media library on iTunes

[dokueki]

I've just moved back to iTunes after a while of trying others. Anyways, I've imported my library, but I deleted it all cause I used a software to arrange the songs better and it renamed most of them. I dragged everything back in, and it imported all my songs well. EXCEPT one set of songs, which for some reason refuse to go in. I have no idea if this is the only set of songs, but it's one I want to get, and I can't. I drag it in, nothing happens. I use Ctrl+O to add the files individually, nothing happens. I add the entire folder to the library again, still nothing happens.

I'm using Windows Vista Home Premium 32bit, with the latest iTunes. I have no iPod or iPhone to sync it with but for a while iTunes is my best option.

 

[tremlock]

check the file type....certain types of files wont load in itunes[i.e. .wav]

 

[dokueki]

They're all MP3s. And I checekd, they're not corrupted either. I played them all in WMP.