dpguesser: 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/sbin/dpguesser - from package: dpsearch

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

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