tmda-pending: 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/tmda-pending - from package: tmda

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

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