faxanswer: 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/faxanswer - from package: hylafax+

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

On Debian possible default full paths are:

/usr/sbin/faxanswer - from package: hylafax-server

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

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