I have squeezecenter 7.3 running on my SmeServer 7.4 box. If you follow the link to the repository in the initial post you will see the name of the rpm has changed to squeezeboxserver-7.4.11.noarch.rpm. That is the reason why yum does not pick it up. There may also be perl modules issues, but I am not there yet.
I do not know yum enough, but when I look inside the xml config files it looks as if there is instructions on how to switch from squeezecenter to squeezeboxserver. There is reference to squeezecenter being obsolete.
Does anyone know if there is a obsolete/supercede mechanism in yum and if so if SmeServer can handle it? In other words should it work?