sgmlwhich: 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/sgmlwhich - from package: sgml-common

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

On Debian possible default full paths are:

/usr/bin/sgmlwhich - from package: sgmltools-lite

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

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