tagpending: 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/tagpending - from package: devscripts

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

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