I'm pretty sure that's not how you are supposed to call the users endpoint. Try this:

http://api.stackoverflow.com/0.8/users/23234

You aren't supposed to pass id in as a url parameter. It is actually part of the url.

Your call is being interpreted as:

http://api.stackoverflow.com/0.8/users

I'm pretty sure that's not how you are supposed to call the users endpoint. Try this:

http://api.stackoverflow.com/0.8/users/23234

You can do this with a vectorized string like so:

http://api.stackoverflow.com/0.8/users/23234;2598;1

You aren't supposed to pass id in as a url parameter. It is actually part of the url.

Your call is being interpreted as:

http://api.stackoverflow.com/0.8/users