Need guidance using arguments in Views with node-comments

I apologize if this is the wrong place for this. If anyone can help, here is what I am trying to do:

I am using Node comments, with a CCK type "Comment", which is basically a normal node (title, body) but with an extra field: "type", which can be five different values ("committee", "patient", "vendor", "administration", "therapist"). I would like to be able to display only the comments of 1 type at a time. I believe I need to use arguments to do this, but I am having trouble getting this to work. I tried cloning the nodecomments view, and adding "Content - Type" to the Arguments view.

It actually seems to work fine when I type the arguments into the "Live Preview", but when I go to the site and type the argument into the URL, I get a 404 error.

I appreciate any advice or tips, thanks!