gnokii-smsd: 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/gnokii-smsd - from package: gnokii-smsd

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

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