pinentry: 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

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 - from package: pinentry

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