vb.net web browser setAttribute Get error "Object reference not set to an instance of an object"

Question

I'm getting stuck trying to write to a text element in a HTML page with the VB.net web browser. I can use the SetAttribute function for almost all text elements on that web page without any problems. However, one text element is giving me trouble. I have already tried many solutions, but I can't get it to work.

When I try to write to this text element I get an error:

ewb1.Document.GetElementById("shipment_titleconsignee_address1").SetAttribute("value", "北海道")

Error: "Object reference not set to an instance of an object."

Other text elements on the same webpage work fine.

Here is the relevant part of the HTML page (sorry it's not well formatted):

I don't understand it well, but it looks like the text input field has some options...

<span class="w120" id="consignee_address01" style="position:relative" name="都道府県">
    <input class="" type="text" id="shipment_titleconsignee_address1" maxlength="8" data-key="shipment.consignee_address1" style="width:120px;" value="">
    <img src="./images/icon_down_gray.png" width="18" height="25" id="shipment_title_imgconsignee_address1" style="vertical-align:middle;margin-left: -20px;">
    <div class="title_combo" id="shipment_title_comboconsignee_address1" style="left: 0px; min-width: 120px; height: 125px; max-height: 125px; background-color: rgb(255, 255, 255); position: absolute; border: 1px solid rgb(204, 204, 204); cursor: default; overflow: hidden auto; z-index: 1001; display: none;">
    <div class="title_option" id="shipment_title_option" value="北海道" style="padding: 3px 5px; width: 100%; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);"><font style="vertical-align: inherit;"><font style="vertical-align: inherit;">Hokkaido</font></font></div>
    <div class="title_option" id="shipment_title_option" value="青森県" style="padding: 3px 5px; width: 100%; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);"><font style="vertical-align: inherit;"><font style="vertical-align: inherit;">Aomori Prefecture</font></font></div>
</span>

I would appreciate any ideas. Thank you.

UPADATE:

Now I can see why it is not working. The code above is from the original web page, but in the vb.net web browser, the html source inside the span is all missing, just like that.

<span class=w120 id=consignee_address01 style=position:relative name=都道府県></span>

This results in an error.

My next question is why and how can I get the vb.net web browser to load all the content?