What you could do is use a small apple script and have it run on login. I wrote one for our network mounts at work which basically pings a server address (you could use whatever address you want, but the one that hosts the network drive would be a good choice). It then mounts the drive if it gets a response from the ping.
The reason I chose to do it this way is that if working away from the office, the network drives are not available from boot up until I've connected to the VPN, so this way I don't get any errors from trying to mount unavailable drives. You could use something like:
Code:
try
if (do shell script "ping -c1 <network address>") contains "1 packets received" then
mount volume "smb://<network drive>"
end if
end try
You'll need to swap <network address> and <network drive> for real addresses or hostnames on your network. I also use smb in this example, but you could use afp instead if your network drive supports it. I then save the script as an Applescript application and set it to run under login items under my account in the system preferences.
This way, your network drive should always be mounted when you login on the network which contains your iTunes media and it should prevent any exclamation marks in your media.
