opensnoop: 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/opensnoop - from package: perf-tools-unstable

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

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