wireless problem - cannot grab ip

i'm using Avaya wireless AP3 and install it at my office
we also using wired network at office
both wired and wireless using the same switch,dhcp,proxy and router
when scan the AP, i can detect 3 ap and all have excellant signal
the problem is, when i'm using wired, i can grab ip but when using wireless, i got 169.x.x.x ip
please help me friends

which hosts on your network are on wireless and which ones are using a wired link?

i'm using the same host..
my notebook have wired and wireless card..
all user have an option wather using wired or wireless

when you are using wireless, i am presuming that you dont have the ethernet cable still attached to the computer. when you try to connect using your inbuilt wireless, go to your command prompt and type 'ipconfig /all'. and see which devices are enabled on your laptop at that moment, and what respective ip addresses they have. that can guide you towards which device is being used at that moment as your primary connection medium

if i'm using wireless connection, i don't use the cable..
yes..i'm issue the ipconfig -all command..
the output is 169.x.x.x ip..
if i'm using wired, i will get 172.x.x.x ip
so what is the solution to solve this problem

this is the layout