mount.ewf: 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:

/sbin/mount.ewf - from package: ewftools

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

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