nib-dicomfs: 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/nib-dicomfs - from package: python-nibabel

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

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