Cisco Wireless :: Clients Timeout On DHCP Lease With Aironet 1141

I'm setting up a Cisco Aironet 1141 (standalone mode, AP) to handle wireless traffic in the office. It gives out 2 mbssids, one of which authenticates domain users through a RADIUS server and places them in an appropriate VLAN (RADIUS options 64, 65, and 81). The other is a guest ssid that uses WPA-PSK and places users in the restricted guest VLAN. Physically, the AP is connected to a 3750 PoE Catalyst, to which RADIUS and DHCP servers are also connected. AP, SSIDs, RADIUS and EAP authentication all work. The configuration given below is a working configuration. People do get authenticated and do get placed in the appropriate vlan. The problem is that, once authenticated, the "Obtaining IP Address" phase on the client hangs and most clients timeout without getting an IP address. Given that the DHCP server is on the same switch and a test simple ASUS Wi-Fi IP gives out the same scenario (except the multiple VLAN) at the speed of light, I don't think that it's a problem with the network connections between clients and the DHCP server. After reading some topics here, I realized that probably other communication will be extremely slow, as well, but haven't tested that for sure. Clients are all non-Cisco - smartphones, notebooks, etc. Most of them are 802.11G, not N.