vscclient: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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/vscclient - from package: libcacard-tools

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