HTML control has javascript errors: how to update the HTML control in AIR ?

I have an AIR application (flex 4.6 or flex 4.7), using  AdobeAIR3.7 or AdobeAir4.0

I use a HTML browser component

    <mx2:HTML id="browser" width="100%" height="100%">

Problem is: when navigating to page, JS gives errors, whereas it works fine with firefox, chrome, ie or safari

When I display the brower navigator.appVersion gives me :

    5.0 (windows;u;fr-FR) AppleWebkit/533.19.4(KHTML, like Gecko) AdobeAIR/3.7

    5.0 (windows;u;fr-FR) AppleWebkit/533.19.4(KHTML, like Gecko) AdobeAIR/4.0

Maybe this is an OLD version : is there a way to UPDATE the internal browser used by Flex ?

JS script I got in the AIR HTML (I don't get in normal browsers):

    ReferenceError: Can't find variable: Uint8Array

    TypeError: Result of expression 'messageHandler.on' [undefined] is not a function.