You need something like this t put before your click.
 
_ExecuteInBackground
_IEAction($oDiv,"click")
Func _ExecuteInBackground()
    Local $sCommand = _
            'Local ' & _
            '$Dummy1 = WinWaitActive("Choose File to Upload", "", 20), ' & _
            '$Dummy2 = Sleep(1000), ' & _
            '$Dummy3 = ControlSetText("Choose File to Upload", "", "Edit1", "C:\Path\To\File.doc;C:\Path\To\File1.doc"), ' & _
            '$Dummy4 = ControlClick("Choose File to Upload", "", "Button1") ' & _
            ''
    $sCommand = '"' & StringReplace($sCommand, '"', '""') & '"'
    ConsoleWrite($sCommand & @CRLF)
    Run(@AutoItExe & ' /AutoIt3ExecuteLine ' & $sCommand)
EndFunc   ;==>_ExecuteInBackground