You could try and set static IPs (distributed by DHCP) for the APs. This way the APs will always get the same IP addresses (reserved) from the router. It might solve the problem, worth a try at least.
It is a good think if most static hardware you use either start from .1 and go up, or from .254 and go down instead of having the entire D range or IPs spread out in the LAN
Anyway might work, might not. Also check the settings in the APs and disable anything you are not using and so on. I assume you are using them as standard APs and nothing special.