pcal: 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/pcal - from package: perl-Calendar-Simple

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

On Debian possible default full paths are:

/usr/bin/pcal - from package: pcal

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