gerbv: 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/gerbv - from package: gerbv

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

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