gif2swf: 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/gif2swf - from package: swftools

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

Error in other languages:
gif2swf: bevel nie gevind nie
gif2swf: comandă negăsită
gif2swf: comando não encontrado
gif2swf: commande introuvable
gif2swf: command not found
gif2swf: käsku ei ole
gif2swf: không tìm thấy lệnh
gif2swf: komanda nerasta
gif2swf: Kommando nicht gefunden.
gif2swf: kommandot finns inte
gif2swf: komut yok
gif2swf: nie znaleziono polecenia
gif2swf: níor aimsíodh an t-ordú
gif2swf: no se encontró la orden
gif2swf: no s'ha trobat l'ordre
gif2swf: opdracht niet gevonden
gif2swf: parancs nem található
gif2swf: perintah tidak ditemukan
gif2swf: príkaz nenájdený
gif2swf: příkaz nenalezen
gif2swf: команда не найдена
gif2swf: командата не е открита
gif2swf: 命令找不到
gif2swf: コマンドが見つかりません