I ran in to a problem where users on the wired LAN could access a Microsoft cluster IP but not through the Cisco Wireless LAN. You could even ping the virtual NLB IP from the WLC itself. I found that the you need to enable a bogus multicast address on the Wireless LAN Controller under general settings and enabling multicast on the global settings.
Controller - Multicast - Enable Multicast Mode
Controller - General - AP Multicast Mode to Multicast and define an IP.
This should be enough if wireless users and the servers are on the same VLAN. Of course, if the servers are on a different VLAN, you need to enable multicast on your switches or routers.
Multicast with Wireless LAN Controllers (WLCs) and Lightweight Access Points (LAPs) Configuration Example