I didn't see clients mentioned in the opening post, so assumed you meant the iAP themselves. Did you have to assigne the iAP manually, or was DHCP working for them?
If DHCP wasn't working for the iAP then I wouldn't expect it to work for clients either.
I'm assuming the router has DHCP set up on VLAN 1.
Does it work for the iAP, and not the clients? or not for either?