problem with Delivery and system:open-url

I can't seem to find the answer to this in the Delivery or General docs.

My app uses system:load-url  to load a URL into the local browser.

My main project file and my delivery script both call (require 
"hqn-web"), which I believe should be sufficient to make sure that 
the module needed for system:open-url  is loaded into my application.

However, even at delivery level 0, when my app makes the call to 
system:open-url I get the following message:
Error: Foreign function HQN-WEB::IC-START trying to call to 
unresolved external function "_ICStart"

Is there some _other_ module I need to load?  Some delivery keyword 
to set?   I am using LispWorks 5 on Mac OS X.  My application is not 
using CAPI.

Any help appreciated.

Chris Perkins
Media Lab, Inc.