pbmtox10bm: command not found

Have You tried accessing the binary with the full path?

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/pbmtox10bm - from package: netpbm-progs

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

On Debian possible default full paths are:

/usr/bin/pbmtox10bm - from package: netpbm

You may install the required package with command apt-get install {package}
Error in other languages:
pbmtox10bm: bevel nie gevind nie
pbmtox10bm: comandă negăsită
pbmtox10bm: comando não encontrado
pbmtox10bm: commande introuvable
pbmtox10bm: command not found
pbmtox10bm: käsku ei ole
pbmtox10bm: không tìm thấy lệnh
pbmtox10bm: komanda nerasta
pbmtox10bm: Kommando nicht gefunden.
pbmtox10bm: kommandot finns inte
pbmtox10bm: komut yok
pbmtox10bm: nie znaleziono polecenia
pbmtox10bm: níor aimsíodh an t-ordú
pbmtox10bm: no se encontró la orden
pbmtox10bm: no s'ha trobat l'ordre
pbmtox10bm: opdracht niet gevonden
pbmtox10bm: parancs nem található
pbmtox10bm: perintah tidak ditemukan
pbmtox10bm: príkaz nenájdený
pbmtox10bm: příkaz nenalezen
pbmtox10bm: команда не найдена
pbmtox10bm: командата не е открита
pbmtox10bm: 命令找不到
pbmtox10bm: コマンドが見つかりません