Network Drive Issues - Win 7 and Server 2008 R2

We have the following network setup:

Server 2008 R2
HostName = S3
IP = 192.168.0.4
Subnet = 255.255.255.0
DNS = 192.168.0.4
Roles = AD-PDC, DNS,DHCP, File & Printer Server, etc...

Firewall = Sonicwall
IP = 192.168.0.1

The following connections are plugged into different ports on the back of the firewall. The networks were placed into 2 different segments because we were running out of DHCP leases.

Wired LAN

• DHCP Range = 192.168.0.100 - 254
• Subnet = 255.255.255.0
• DNS Server = 192.168.0.4
• Gateway = 192.168.0.1

Wireless LAN

• DHCP Range =172.16.31.100 - 254
• subnet = 255.255.255.0
• DNS Server = 192.168.0.4
• Gateway = 172.16.31.1

The sonicwall has and IP helper object to direct the DHCP traffic from the wireless to the LAN.

The issue we are having is that when users move from a wired connection, LAN, to the wireless connection their network drives disconnect and nothing short of restarting the computer while connected to the wireless will make the drives reconnect. I have this issues on almost every computer in my office and can't figure out how to resolve it short of changing the subnet on the LAN to .254 and just adding the wireless back into that range. Would anyone know of a better way to resolve this?