ifscheme-mapping: 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:

/sbin/ifscheme-mapping - from package: ifscheme

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

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