gifcompose: 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/gifcompose - from package: giflib-utils

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

On Debian possible default full paths are:

/usr/bin/gifcompose - from package: giflib-tools

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

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