c2faxrecv: 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/bin/c2faxrecv - from package: capi4hylafax

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

Error in other languages:
c2faxrecv: bevel nie gevind nie
c2faxrecv: comandă negăsită
c2faxrecv: comando não encontrado
c2faxrecv: commande introuvable
c2faxrecv: command not found
c2faxrecv: käsku ei ole
c2faxrecv: không tìm thấy lệnh
c2faxrecv: komanda nerasta
c2faxrecv: Kommando nicht gefunden.
c2faxrecv: kommandot finns inte
c2faxrecv: komut yok
c2faxrecv: nie znaleziono polecenia
c2faxrecv: níor aimsíodh an t-ordú
c2faxrecv: no se encontró la orden
c2faxrecv: no s'ha trobat l'ordre
c2faxrecv: opdracht niet gevonden
c2faxrecv: parancs nem található
c2faxrecv: perintah tidak ditemukan
c2faxrecv: príkaz nenájdený
c2faxrecv: příkaz nenalezen
c2faxrecv: команда не найдена
c2faxrecv: командата не е открита
c2faxrecv: 命令找不到
c2faxrecv: コマンドが見つかりません