gnee: 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/gnee - from package: Xnee

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

On Debian possible default full paths are:

/usr/bin/gnee - from package: gnee

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

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