lap 1252 is shown in CDP but not associated with wlc 2112 software version 5.1
Ok. On the AP, do a "dir" command. You should see two IOS in the list. One of the IOS has the "rcv" between the filename. If you see this then DELETE the second/third IOS using the command "delete /f /r flash:". Reboot. Once the AP has rebooted, run the command "lwapp ap ip address" command again.
Hope this helps.