yasm: 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/yasm - from package: yasm

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

On Debian possible default full paths are:

/usr/bin/yasm - from package: yasm

You may install the required package with command apt-get install {package}

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