2 out 100 iPads can't get IP from DHCP

Question

Hi,
The school were I worked use 100 iPad 3 for students (they were bought at the same time); Out of 100 iPads being used, 2 is always having problem getting IP from DHCP (connected but did not get IP or some random IP), We used a mixed of Linksys E3000, E4500, and a couple of old Linksys WRT54G routers, we are using hidden SSID and WEP
once in a while (if I try to disconnect/reconnect enough times) it will get IP from DHCP, but after a few days, the problem will appear again
I don't have a say on the use of hidden SSID and the usage of the aging WEP protocol, and the other 98 iPads were not having any problem connecting to those routers
I have tried updating the iPad, reset network settings, reset all settings, and even restoring the 2 iPads, and they were still having problem getting IP from DHCP
Those iPads have no problem connecting to the internet if the IP is made static (well today, one iPad can connect to the internet, but can't browse? is it DNS problem)
Can I claim to Apple Authorized Service Provider? (no Apple Store here), since if they test it I'm pretty sure the iPad will connect to their WiFi (seems like the student have no problem connecting at their WiFi at home, just not at school (which is troublesome))
I read somewehere that certain iPads are not compatible with some routers, is it true
any suggestions

Answer 1

With the static ip address try:
Google provides free dns lookup.  Their numbers are:
8.8.8.8
8.8.4.4
I'd take the issue up with apple.
Sneak in another router that works with the devices.
Robert