pegasus-dagman: command not found

Have You tried accessing the binary with the full path?

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/pegasus-dagman - from package: pegasus-wms

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