wmlunits: 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/wmlunits - from package: wesnoth-tools

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

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