pcdovtoppm: 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

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/pcdovtoppm - from package: netpbm-progs

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