[CentOS] asking for a repo

Surfing on the web I had found a repo, I want to know how safe it is??? the URL is http://www.alcancelibre.org/al/el5/ sorry if a make any mistake on my writing. thanks to all -- “Nuestra recompensa se encuentra en el esfuerzo y no en el resultado. Un esfuerzo total es una victoria completa”

[CentOS] Updating RPMS on system [fails]

I had a problem when I start my PC the system start to starts services and check itselfs but when it arrives to Updating RPMS on system always fails I want to know why? -- “Nuestra recompensa se encuentra en el esfuerzo y no en el resultado. Un esfuerzo total es una victoria completa”.