Wireless Network refresh

I have Avaya 1G switches and just installed Brocade 650 wireless access points
for wifi in our school building. I have assigned one static ip address for the router to access our wired network,
with the router then assigning ip's through DHCP. All works, however, students can access the network,
surf to the web with ease, but in accessing network directories they are unable to do it consistently.
Connected directories frequently refreshing themselves, making for inability for the student to access
info from that directory. I know the server is probably seeing many laptops with the same ip address, but can
I change something to alleviate this problem. Server is Win 2008, with students using Latitude 6430
with Win 7 Pro.

So what is doing all the DHCP? Is this a domain? Are the switches managed as in layer 3 or unmanaged? What kinda permissions you have on the folder they are trying to get to?