pinentry-curses: 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 CentOS possible default full paths are:

/usr/bin/pinentry-curses - from package: pinentry

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/pinentry-curses - from package: pinentry-curses

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

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