tsclient: 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/tsclient - from package: tsclient

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

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