tomoyo-pstree: 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/tomoyo-pstree - from package: tomoyo-tools

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

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