gfan_tropicalbasis: command not found

Have You tried accessing the binary with the full path?

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/gfan_tropicalbasis - from package: gfan

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