sgml2latex: 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 CentOS possible default full paths are:

/usr/bin/sgml2latex - from package: linuxdoc-tools

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/sgml2latex - from package: linuxdoc-tools

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

Error in other languages:
sgml2latex: bevel nie gevind nie
sgml2latex: comandă negăsită
sgml2latex: comando não encontrado
sgml2latex: commande introuvable
sgml2latex: command not found
sgml2latex: käsku ei ole
sgml2latex: không tìm thấy lệnh
sgml2latex: komanda nerasta
sgml2latex: Kommando nicht gefunden.
sgml2latex: kommandot finns inte
sgml2latex: komut yok
sgml2latex: nie znaleziono polecenia
sgml2latex: níor aimsíodh an t-ordú
sgml2latex: no se encontró la orden
sgml2latex: no s'ha trobat l'ordre
sgml2latex: opdracht niet gevonden
sgml2latex: parancs nem található
sgml2latex: perintah tidak ditemukan
sgml2latex: príkaz nenájdený
sgml2latex: příkaz nenalezen
sgml2latex: команда не найдена
sgml2latex: командата не е открита
sgml2latex: 命令找不到
sgml2latex: コマンドが見つかりません