gearman_top: 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/gearman_top - from package: mod-gearman-tools

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

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