Still we dont have a clear view of what you got...
If your Core swtich or another L3 switch is routing you could check if the iphelper is there correctly configured.
If the core switch or the switch were you plugged the WC had a trunk which is trunking the WLAN vlans rebooted and you didnt save the config it might have loose the configuration of the trunk and thats why you not getting anything(this happened to a client of mine actually, with their captive portal)
It could be many things but we would need to know how is set up otherwise it will be really hard for us knowing or try to help you...
We need to know how its set up, it is a good chance that your Wireless solution is not the problem... it could be a problem maybe on your switces like a vlan tag missing... a missing ip helper... etc.
If you can give us more info we might be able to help you.... i mean more info about how is it setup like who is routing, basic information like that, do the ip helper is correctly configured for example in the core switch?