Songs won't transfer from hard drive to iTunes??

I'm working on moving my music collection from my CDs and hard drive into iTunes to put on my iPod, but it only imported about 800 songs and won't start back up again. I've tried restarting everything, doing single songs instead of folders, and it just won't do any more songs. I still have thousands left. Is there somehow a limit as to how many songs you can import into your iTunes library? Any suggestions? Please help.