You might want to add print statements just before the function exits to display the url and response, then try typing the same url into a web browser to see if it is working:
print "url=" + url
print "response=" + response
Also, it may be unrelated to your problem, but it might be a good idea to escape the parameters in the url query string in case they contain any weird characters:
ut = CreateObject ("roUrlTransfer") ' Create a roUrlTransfer object
'
'
url = url + ut.Escape (category) ' ... etc. Escape each of your query parameters
And like RokuJoel said above, escape the parameters containing "(". And I think the asterisks may need to be escaped too, e.g:
url = url + "&utme=5" + ut.Escape ("(")
'
'
url = url + ut.Escape ("*")
'
url = url + ut.Escape (")(1)")