tiffcrop: 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/bin/tiffcrop - from package: libtiff

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

On Debian possible default full paths are:

/usr/bin/tiffcrop - from package: libtiff-tools

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

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