Highlight Text in PDF using JSObject

I am doing a PDF compare application using VB.NET and JSObject. I did all the compare logic and extracted all the mismatching words and their X-Y co-ordinates. Now its the time to highlight all the acquired co-ord with some color. I get 8 values when I get access the co-ord using the below fn.

oCoord = JSO.getPageNthWordQuads(Page, Word)

I tried up the following with simple X-Y co-ordinates it works great. But when I give using the co-ordinates what I get from the exact location (i.e., I get 8 values which describe a rectangle), I get the following error,

"Value does not fall within the expected range."

Here is the failed code -

page = pdDoc.AcquirePage(0)

'' I get pageRect.Y = 842 and pageRect.X = 595
pageRect = page.GetSize

popupRect(0) = 36D
popupRect(1) = 673.171997070312D
popupRect(2) = 96.69580078125D
popupRect(3) = 673.171997070312D
popupRect(4) = 36D
popupRect(5) = 659.300109863281D
popupRect(6) = 96.69580078125D
popupRect(7) = 659.300109863281D

annot = jso.AddAnnot
props = annot.getProps
props.Type = "Highlight"
annot.setProps(props)
props = annot.getProps
props.page = 0
props.popupRect = popupRect
props.strokeColor = jso.Color.Yellow
annot.setProps(props)

What is that I am missing? Or do I need to do some manipulation with the co-ordinates.

Here is the code which works fine -

page = pdDoc.AcquirePage(0)

'' I get pageRect.Y = 842 and pageRect.X = 595
pageRect = page.GetSize

popupRect(0) = 0
popupRect(1) = pageRect.y
popupRect(2) = 200
popupRect(3) = pageRect.y

annot = jso.AddAnnot
props = annot.getProps
props.Type = "Highlight"
annot.setProps(props)
props = annot.getProps
props.page = 0
props.popupRect = popupRect
props.strokeColor = jso.Color.Yellow
annot.setProps(props)