couchapp: 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/couchapp - from package: couchapp

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

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