es2gears_screen: 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/bin/es2gears_screen - from package: mesa-utils-extra

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

Error in other languages:
es2gears_screen: bevel nie gevind nie
es2gears_screen: comandă negăsită
es2gears_screen: comando não encontrado
es2gears_screen: commande introuvable
es2gears_screen: command not found
es2gears_screen: käsku ei ole
es2gears_screen: không tìm thấy lệnh
es2gears_screen: komanda nerasta
es2gears_screen: Kommando nicht gefunden.
es2gears_screen: kommandot finns inte
es2gears_screen: komut yok
es2gears_screen: nie znaleziono polecenia
es2gears_screen: níor aimsíodh an t-ordú
es2gears_screen: no se encontró la orden
es2gears_screen: no s'ha trobat l'ordre
es2gears_screen: opdracht niet gevonden
es2gears_screen: parancs nem található
es2gears_screen: perintah tidak ditemukan
es2gears_screen: príkaz nenájdený
es2gears_screen: příkaz nenalezen
es2gears_screen: команда не найдена
es2gears_screen: командата не е открита
es2gears_screen: 命令找不到
es2gears_screen: コマンドが見つかりません