sysrqd: 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/sbin/sysrqd - from package: sysrqd

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

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