help with "IF" command

Hello again.

Im trying to setup a small script to basiclly say

"If XXX is present do this, Otherwise Carry on and do this..."


This is the script i have

$o_frame = _IEFrameGetCollection($oIE, 2)
$Captcha = _IEGetObjById($o_frame,"siimage")
If ($Captcha.ID) = "siimage" Then
            msgbox("","work","worked")
        EndIf
msgbox("","Nowork","Nowork :(")
 

If the object is on screen it works perfect, displays the Worked box and then after displays the "Nowork" box which is exactly what i want it to do, However if the ID isnt on the page i get an error and the script stops.

"C:\Users\ant.Ant-PC\Desktop\Captcha.au3 (26) : ==> Variable must be of type "Object".:
If ($Captcha.ID) = "siimage" Then
If ($Captcha^ ERROR"

Anyhelp is apreciated thanks.