fxotune: 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/sbin/fxotune - from package: dahdi-tools

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

On Debian possible default full paths are:

/usr/sbin/fxotune - from package: dahdi

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

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