So the form is being submitted with a http POST method. With POST, the values are passed in the body of the request, instead of added to the URL using the ?a=1&b=2 syntax. When then POST comes into the Arc server, it pulls the arguments from the request body, ignoring the URL.
What you want is to include a hidden input value in your form:
(gentag input type 'hidden name 'parm value 324342)
That way you'll get the parm value passed along in the form values.
Your use of "url" as a global variable is a bad idea if two users happened to request "test" at the same time. By the time "(do-it url)" is called, "url" might have been set to the other value by the other invocation of "test".