mkgmap: 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/mkgmap - from package: mkgmap

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

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