tiffgt: 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/tiffgt - from package: libtiff-opengl

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

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