check-enhancements: 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 Debian possible default full paths are:

/usr/bin/check-enhancements - from package: debian-goodies

You may install the required package with command apt-get install {package}

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