pwo2xsf: 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/pwo2xsf - from package: xcrysden

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

Error in other languages:
pwo2xsf: bevel nie gevind nie
pwo2xsf: comandă negăsită
pwo2xsf: comando não encontrado
pwo2xsf: commande introuvable
pwo2xsf: command not found
pwo2xsf: käsku ei ole
pwo2xsf: không tìm thấy lệnh
pwo2xsf: komanda nerasta
pwo2xsf: Kommando nicht gefunden.
pwo2xsf: kommandot finns inte
pwo2xsf: komut yok
pwo2xsf: nie znaleziono polecenia
pwo2xsf: níor aimsíodh an t-ordú
pwo2xsf: no se encontró la orden
pwo2xsf: no s'ha trobat l'ordre
pwo2xsf: opdracht niet gevonden
pwo2xsf: parancs nem található
pwo2xsf: perintah tidak ditemukan
pwo2xsf: príkaz nenájdený
pwo2xsf: příkaz nenalezen
pwo2xsf: команда не найдена
pwo2xsf: командата не е открита
pwo2xsf: 命令找不到
pwo2xsf: コマンドが見つかりません