sgml-spell-checker: 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/sgml-spell-checker - from package: sgml-spell-checker

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

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