pbmtext: 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/pbmtext - from package: netpbm-progs

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

On Debian possible default full paths are:

/usr/bin/pbmtext - from package: netpbm

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

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