triggers-diff.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/triggers-diff.pl - from package: dotlrn
/usr/share/openacs/bin/triggers-diff.pl - from package: openacs

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

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