pg_xlogdump: 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/lib/postgresql/9.4/bin/pg_xlogdump - from package: postgresql-9.4

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

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