xbmtopbm: 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/xbmtopbm - from package: netpbm-progs

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

On Debian possible default full paths are:

/usr/bin/xbmtopbm - from package: netpbm

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

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