ActiveResource Breaking Under FastCGI

I'm developing a web service in rails which uses JSON as the transport format. I also have a front end rails site that talks to that web service to retrieve various bits of data. I'm using ActiveResource to accomplish that.

When running my unit tests for the ActiveResource clients I've written against a WebBrick server, they all pass fine. However when I run them against the exact same application code running on FastCGI (on Dreamhost) it appears that the the save method is partially broken.

The save is successful and my server returns a 201 HTTP status code. The new entry gets added to the DB. However, the ID attribute of the entry is blank. When I run this rails application on WebBrick however, it's populated with the ID attribute of the saved item.

Both servers are running the same version of Ruby and Rails. Anyone have any idea what could be going on?

Eonflare