cancel.cups: command not found

Have You tried accessing the binary with the full path?

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/bin/cancel.cups - from package: cups

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