Try getting the collection of anchor tags, with:
GetElementsByTagName("a")
Then, iterate that collection using as much logic as you can to ensure you’re clicking the right button.
For each l in ie.document.getElementsByTagName("a")
If l.ClassName = "hqt_button" Then
l.Click
Exit For
Next
If there are multiple anchors with the same classname, you could do:
If l.ClassName = "hqt_button" AND l.Href = ""https://stackoverflow.com/questions/24638533/javascript:void(0): onclick=HeaderBox.trySubmit()" Then
l.Click
Exit For
Next
Alternatively
If you are using IE9+ you could use the GetElementsByClassName
method.
GetElementsByClassName("hqt_button")