DWR, Dojo, and AJAX issue

Hello all,

I'm working on a relatively simple dojo module that allows for 
lazily-loading DWR services.  Reason: if I have a widget that requires a 
DWR service, I don't want to have to make sure the enclosing HTML page 
has the appropriate script tags -- I want to say inside my dojo module: 
mycompany.dwr.loadDWRService("WidgetDWRService");

My solution so far works great in FF2.0, but I'm having trouble getting 
it to work in IE7 -- I think the DWR JavaScript files aren't evaluating 
correctly in IE7.

Here is my module; hoping someone familiar with dojo (I'm using 0.4.1) 
and DWR (I'm using 1.1.3) can help me figure out the issue and/or a 
workaround:
================================
dojo.provide("dynedge.dwr.common");

mycompany.dwr.loadDWREngine = function() {
 if (! dj_undef("DWREngine")) {
   dojo.debug("Engine already loaded");
   return;
 }

 dojo.debug("Result of load: " + 
dojo.hostenv.loadPath("../../dwr/engine.js"));
 if (dj_undef("DWREngine")) {
   dojo.debug("DWREngine doesn't exist -- loading failed");
 } else {
   dojo.debug("DWREngine successfully loaded");
 }
};

mycompany.dwr.loadDWRService = function(/*String*/dwrName) {
 // First trying to load the DWREngine
 mycompany.dwr.loadDWREngine();

 if (! dj_undef(dwrName)) {
   dojo.debug(dwrName + " already loaded");
   return;
 }

 dojo.debug("Result of service load: "
     + dojo.hostenv.loadPath("../../dwr/interface/" + dwrName + ".js"));
 if (dj_undef(dwrName)) {
   dojo.debug(dwrName + " doesn't exist -- loading failed");
 } else {
   dojo.debug(dwrName + " successfully loaded");
 }
};
================================

In my dojo widget, I'm making the following call:  
mycompany.dwr.loadDWRService("WidgetDWRService");

In Firefox 2.0.0.1, this is the dojo.debug output from above:
Result of load: true
DWREngine successfully loaded
Result of service load: true
WidgetDWRService successfully loaded
Engine already loaded

In Internet Explorer 7.0.5730.11, this is the dojo.debug output from above:
Result of load: true
DWREngine doesn't exist -- loading failed
Result of service load: true
WidgetDWRService doesn't exist -- loading failed


Anyone have any ideas why this would work perfectly in Firefox but not 
in IE7, and how I could go about debugging it?  I know IE7 is a little 
awkward with AJAX support with its ActiveX and native XMLHttpRequest 
objects each being a little different, but I don't know enough about 
that to know if it's what the issue is here.

Thanks much,
Jim