So you're actually running Trixbox rather than CentOS - what most here will tell you - these are not really the same. Maybe reading this article on the subject will help: ... [by milosb]
on 02/10/2010 – Made popular on 02/10/2010
I have a problem with installing yum in CentOS (version 5.3, 64bits). My CentOS not yet install yum, so i can't install other package that I need. I found out one article that show how to install yum on CentOS (both 32bits and 64bits), but it doesn't work for me.