need help for Checkbox+Dlink

Hi,

I am quite new to AutoIT, after playing around with it so far, I found out what I wanted through help files and tutorials. However this time I can't figure how to make my script work.
I wanna click on checkbox ''Enable Wireless''

part of the HTML code

<input id="w_enable" type="checkbox" checked="" onclick="disable_wireless();" value="1" name="w_enable" default="false">

My Autoit Script

#include <IE.au3>

$oIE = _IECreate("http://192.168.0.1")
$password = _IEGetObjByName($oIE, "log_pass")
_IEPropertySet($password, 'innerText',"")
$button = _IEGetObjById ($oIE, "login")
_IEAction ($button, "click")

$oWireless=_IENavigate($oIE,"http://192.168.0.1/wireless.asp")
$oForm = _IEFormGetObjByName($oWireless, "w_enable")
$oForm.checked = true

It says $oForm isn't an object.

Anyone can figure this out? Or point me some tips, I've also tried using .fire event and _IEFormElementCheckBoxSelect($oForm, "w_enable","", 1, "byValue")  but none of the script I wrote worked.