problem running Couchbase Server on OS X

I'm running into an issue with the OSX install of Couchbase and was hoping you might be able to shed some light. I've installed/reinstalled several flavors of couchbase for OSX, including:

community 4.0.0
community 4.0.0 (el capitan build)
enterprise 4.1.1
enterprise 4.5.0

and in each case I have exercised the following:

(1) Copy Couchbase Server.app to /Applications
(2) Used Couchbase status menu to access the Admin Console
(3) Select "Setup" in Admin Console
(4) Maintain all defaults in "Configure Server" UI, click Next.
(5) The Admin Console hangs indefinitely.

Using firebug and tcpdump, it looks like the rename REST API call may be the issue. It looks like the UI is making this call:

=====================================
POST /node/controller/rename HTTP/1.1
Host: 127.0.0.1:8091
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:46.0) Gecko/20100101 Firefox/46.0
Accept: text/plain, /; q=0.01
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Content-Type: application/x-www-form-urlencoded
invalid-auth-response: on
Cache-Control: no-cache
Pragma: no-cache
ns-server-ui: yes
X-Requested-With: XMLHttpRequest
Referer: http://127.0.0.1:8091/index.html
Content-Length: 18
Connection: keep-alive

hostname=127.0.0.1
=====================================

but the server is responding to the request with an immediate FIN at the TCP layer and does not respond to the request at all at the HTTP layer. It's not an RST, though, and the server does continue running, so I don't imagine the server is crashing.

I've checked the logs in ~Library/Application Support/Couchbase/var/lib/couchbase/logs but haven't seen anything that appears to correspond to the problem. I've also done some hunting around online and haven't seen anything similar. On a positive note, I've checked with another member of our team who is apparently not seeing the same problem on a similarly outfitted MacBook Pro - so could be something particular to my setup.