pconnect: 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:

/opt/opennx/bin/pconnect - from package: opennx

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

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