Query value is passed correctly but does not return any results in the query API string

I have a form that submit a query to an API. the parameter is passed correctly to the next page and I can print it as a test, but it is not passed to the API query

q='%"&Request.QueryString("id")&"%'

sometimes the result is just generic and does not include the query parameter. I can print it and the parameter is definitely passed to the page but it is just ignored or return an error: System.NullReferenceException: Object reference not set to an instance of an object. Any ideas on how to fix this? not sure if it is a formatting issue or the way the page is loaded.

This requests the query parameter and displays it on the page as a test (correct value is returned)

Form page:

dim intID as String
intID = Request.QueryString("id")
Response.write(intID) 

Result Page:

This is the Query Parameter section:
Dim doc As New XmlDocument()
doc.Load("http://api.tradedoubler.com/1.0/products.xml; q='%"&Request.QueryString("id")&"%';tdCategoryId=168;%20category=test?token=B17495243749DAC9660980F6FB98495928DDX123")

So when I use the browser - copy the link to the url with a parameter e.g. q=spain, I get the correct results but when embedded in the asp.net page, it doesn't work