vsyasm: 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/vsyasm - from package: yasm

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

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