I tried nx3 using a freshly rebooted server (c4, i686).  It did *not* have the
/tmp/.X11-unix directory.

Because /tmp/.X11-unix does not exist, I got this error in ~/.nx/foo-bar-xxxx/clients

_XSERVTransmkdir: ERROR: euid != 0,directory /tmp/.X11-unix will not be created.
_XSERVTransSocketUNIXCreateListener: mkdir(/tmp/.X11-unix) failed, errno = 2
_XSERVTransMakeAllCOTSServerListeners: failed to create listener for local

This resulted in an extremely slow session.  I manually created the directory with
the correct owner and permission bits (root:root 1777) and all was OK after that.

I see a potential problem here.  Servers may not necessarily have this required 
directory just like in my case and nx does not have enough privilege to create one. 

Who is to blame in this situation?