SP2.5 is failing to start : CRIT Shibboleth.Listener : failed to bind to socket.

[Joshua Brodie]

I upgraded a test SP we have running on RHEL6 to Shibboleth SP 2.5
(via YUM update).

SP is now failing to start - the 'shibd.log' file showed the
following. Aside from port443 for the Apache, there are no other ports
listening - any tips on where to look?

2012-08-09 17:55:20 INFO Shibboleth.Listener : listener service starting
2012-08-09 17:55:20 ERROR Shibboleth.Listener : socket call (bind)
resulted in error (13): no message
2012-08-09 17:55:20 CRIT Shibboleth.Listener : failed to bind to socket.
2012-08-09 17:55:20 INFO Shibboleth.Config : shibboleth 2.5.0 library
shutting down