lib: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/share/sgml/docbook/xsl-ns-stylesheets-1.75.2/epub/bin/lib - from package: docbook5-style-xsl
/usr/share/sgml/docbook/xsl-stylesheets-1.75.2/epub/bin/lib - from package: docbook-style-xsl

You may install the required package with command yum install {package}

Error in other languages:
lib: bevel nie gevind nie
lib: comandă negăsită
lib: comando não encontrado
lib: commande introuvable
lib: command not found
lib: käsku ei ole
lib: không tìm thấy lệnh
lib: komanda nerasta
lib: Kommando nicht gefunden.
lib: kommandot finns inte
lib: komut yok
lib: nie znaleziono polecenia
lib: níor aimsíodh an t-ordú
lib: no se encontró la orden
lib: no s'ha trobat l'ordre
lib: opdracht niet gevonden
lib: parancs nem található
lib: perintah tidak ditemukan
lib: príkaz nenájdený
lib: příkaz nenalezen
lib: команда не найдена
lib: командата не е открита
lib: 命令找不到
lib: コマンドが見つかりません