ufl-convert: 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/ufl-convert - from package: python-ufl

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

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