ITUNES not working with My Book on network

I have my itunes library on the external drive which is connected to a linksys router and shared on my network over wifi.

It appears in my laptop as network drive Z:. I can use the external from windows and everything works fine but when i start itunes although it can play all songs , cannot add more tunes to the library or modify the ones i have, they dissapear. Any idea?

Sounds like you have read-only access, and can’t write to the drive.  You’d have to change that at the router, in the Administration settings.