tiffcheck: 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/tiffcheck - from package: hylafax+-client

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

On Debian possible default full paths are:

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

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

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