imgvinfo: 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/imgvinfo - from package: imgvtopgm

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

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