dh_installmime: command not found

Have You tried accessing the binary with the full path?

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/dh_installmime - from package: debhelper

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