gnumeric: 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/gnumeric - from package: gnumeric

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

On Debian possible default full paths are:

/usr/bin/gnumeric - from package: gnumeric

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

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