pg_7.2to7.3_upgrade_helper.pl: 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/share/dotlrn/bin/pg_7.2to7.3_upgrade_helper.pl - from package: dotlrn
/usr/share/openacs/bin/pg_7.2to7.3_upgrade_helper.pl - from package: openacs

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

Error in other languages:
pg_7.2to7.3_upgrade_helper.pl: bevel nie gevind nie
pg_7.2to7.3_upgrade_helper.pl: comandă negăsită
pg_7.2to7.3_upgrade_helper.pl: comando não encontrado
pg_7.2to7.3_upgrade_helper.pl: commande introuvable
pg_7.2to7.3_upgrade_helper.pl: command not found
pg_7.2to7.3_upgrade_helper.pl: käsku ei ole
pg_7.2to7.3_upgrade_helper.pl: không tìm thấy lệnh
pg_7.2to7.3_upgrade_helper.pl: komanda nerasta
pg_7.2to7.3_upgrade_helper.pl: Kommando nicht gefunden.
pg_7.2to7.3_upgrade_helper.pl: kommandot finns inte
pg_7.2to7.3_upgrade_helper.pl: komut yok
pg_7.2to7.3_upgrade_helper.pl: nie znaleziono polecenia
pg_7.2to7.3_upgrade_helper.pl: níor aimsíodh an t-ordú
pg_7.2to7.3_upgrade_helper.pl: no se encontró la orden
pg_7.2to7.3_upgrade_helper.pl: no s'ha trobat l'ordre
pg_7.2to7.3_upgrade_helper.pl: opdracht niet gevonden
pg_7.2to7.3_upgrade_helper.pl: parancs nem található
pg_7.2to7.3_upgrade_helper.pl: perintah tidak ditemukan
pg_7.2to7.3_upgrade_helper.pl: príkaz nenájdený
pg_7.2to7.3_upgrade_helper.pl: příkaz nenalezen
pg_7.2to7.3_upgrade_helper.pl: команда не найдена
pg_7.2to7.3_upgrade_helper.pl: командата не е открита
pg_7.2to7.3_upgrade_helper.pl: 命令找不到
pg_7.2to7.3_upgrade_helper.pl: コマンドが見つかりません