The permissions look fine, but the modification date of the qd.darwin indicates that it hasn't been updated for months.
The file size matches the Mac OS X Universal binary released released 26 October 2009 (fr 074) and the one released 17 November 2009 (fr 075), but your FCI install shows that the last version it has was released 10 September 2009 (fr 073).
In my webserver logs I see that your last normal qd update was on 24/Sep/2009:06:05:02 +0200, from 24/Sep/2009:07:05:05 +0200 on it has been failing. The update script notices that the OSX qd binary is out of date, downloads it, but fails to save it, so the next update it sees that it needs to update the binary, downloads it, but fails to save it. This cycle repeats ever since.
You currently download 211576 bytes when requesting the Mac OS X Universal binary, which is the file size of the current binary. So you do download the full binary, but after this something goes wrong.
If you have AppArmor enabled, you may want to try to disable it, and try a forced qd update again. This is about the only thing I can think of which may prevent you from downloading the Mac OS X Universal binary, which I don't run into on the systems where I have tested (there, SE Linux and AppArmor are about the first to be disabled). See the
Ubuntu AppArmor documentation for the procedure to disable AppArmor.