1.7 Custom Build issues

Bear with me as I'm new to both Dojo and builds, and my Google Fu has come up
short. Some of the documentation and tutorials I've found are confusing to
me, I think due to old and new approaches.

I tried making a custom build from a sample profile locally, but then I
discovered the web build tool and used that.

In either case, I specified in the build every package that my source file
"require"s, but I'm still seeing unsatisfied requests for external js files
(and JS errors, of course).

My source file has:
                        dojo.require("dojox.mobile");
                        dojo.require("dojox.mobile.parser");
                        dojo.require("dojox.mobile.compat");
                        dojo.require("dojox.mobile.deviceTheme");

And my custom build included all of those plus the two specific dojox.mobile
classes I'm using in the page. 

But when I load my custom dojo.js instead of the CDN one, I get 404 errors
for /dojo/dijit/registry.js, /dojo/dijit/_Contained.js,
/dojo/dijit/_Container.js, and /dojo/dijit/_WidgetBase.js.

(The first JS error seems to be at 

var dm = lang.getObject("dojox.mobile", true);

Do I just need to add those packages explicitly to the build? I thought the
prereqs were supposed to be pulled in automatically?