pymcapostbatch: 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 Debian possible default full paths are:

/usr/bin/pymcapostbatch - from package: pymca

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

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