The short answer is: is there a good reason not using "util_current_location"?
Determining the "location" is complex (the same server might be reached over different domain names and drivers) and depends to a great deal on the virtual hosting setup or whether the server runs behind a reverse proxy.
Make sure, the OpenACS config file uses global modules (in ns/modules, see e.g. [1]). A quick test on openacs.org shows the right domain name.
