edit-faxcover: 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/edit-faxcover - from package: hylafax+-client

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

On Debian possible default full paths are:

/usr/bin/edit-faxcover - from package: hylafax-client

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

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