Music on server

[KAT]

I used to be able to access my songs on my server from any of my 
computers but with the latest updates (last 3 months or so) when i 
select a song iTunes asks if i want to locate the song. I go through 
the process of logging in to the server share point and selecting the 
song and it plays. The next song I select we go through the same 
process. What's up with this? I originally mounted the share point and 
went to the advanced prefs and selected the music folder but it just 
doesn't work. HELP please my wife is driving me nuts wanting her music 
to use in iMovie and she can't get to it either.

KAT