pickthread: 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/share/doc/mh-book/examples/mh/bin/pickthread - from package: mh-book

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

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