Cisco Wireless :: 2960G / AIR-AP1142N-E-K9 Ethernet Interface Stops Working?

I installed two AIR-AP1142N-E-K9 access points, running a fairly simple config, WPA2 PSK, with AES cipher, both the same SSID.The two access points are connected to Cisco 2960G switches, which are in turn connected to each other, again without any fancy config options, no VLAN's ed.
 
After a random while, varying from 30 minutes to 15 hours, the access points will stop sending/recieving traffic on the ethernet interface.The units don't stop at the same moment, this also varies seemingly random. It's not related to load or the amount of clients (1 to 15).Only turning on one unit doesn't make any difference.
 
The units keep sending out their SSID, you can associate to them, but the DHCP requests aren't passed on to the DHCP server which is connected to one of the 2960G's.If you wirelessly connect to the AP and set a manual IP adress you can reach the webinterface and telnet/ssh to the access point. The ethernet link is reported as being up on the access point. Also the switch reports a link on the port to which the access point is connected.Resetting the link does have no effect. The log doesn't mention any errors or warnings.Power cycling or reloading the access point will put it back in working order for a varying amount of time.
 
Access point version:
 
Cisco IOS Software, C1140 Software (C1140-K9W7-M), Version 12.4(21a)JA1, RELEASE SOFTWARE (fc1)
 
Access point config:
 
!
! Last configuration change at 14:41:40 +0100 Sat May 12 2012 by admin
! NVRAM config last updated at 14:41:40 +0100 Sat May 12 2012 by admin
!
version 12.4
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec

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