gmime-uuencode: 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/gmime-uuencode - from package: gmime-bin

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