You login with filezilla, go to the music directory, and count them by hand.
Unless filezilla has a feature that counts files in a directory for you.
I guess you could login with putty, and I could give you the linux commands to count the number of files.
Login with this:
http://www.chiark.greenend.org.uk/~sgta ... nload.html
Then use these text commands:
cd music
ls –l | wc –l