gexec: 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/gexec - from package: gexec

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