launch-ant.sh: 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/doc/libcommons-launcher-java/examples/bin/launch-ant.sh - from package: libcommons-launcher-java

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

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