pst2dii: 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/bin/pst2dii - from package: libpst

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

On Debian possible default full paths are:

/usr/bin/pst2dii - from package: pst-utils

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

Error in other languages:
pst2dii: bevel nie gevind nie
pst2dii: comandă negăsită
pst2dii: comando não encontrado
pst2dii: commande introuvable
pst2dii: command not found
pst2dii: käsku ei ole
pst2dii: không tìm thấy lệnh
pst2dii: komanda nerasta
pst2dii: Kommando nicht gefunden.
pst2dii: kommandot finns inte
pst2dii: komut yok
pst2dii: nie znaleziono polecenia
pst2dii: níor aimsíodh an t-ordú
pst2dii: no se encontró la orden
pst2dii: no s'ha trobat l'ordre
pst2dii: opdracht niet gevonden
pst2dii: parancs nem található
pst2dii: perintah tidak ditemukan
pst2dii: príkaz nenájdený
pst2dii: příkaz nenalezen
pst2dii: команда не найдена
pst2dii: командата не е открита
pst2dii: 命令找不到
pst2dii: コマンドが見つかりません