cimprovagt: 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/sbin/cimprovagt - from package: tog-pegasus

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

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