mrtransform: 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/lib/mrtrix/bin/mrtransform - from package: mrtrix

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

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