psize: 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/psize - from package: pdb2pqr

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

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