ytasm: 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/ytasm - from package: yasm

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

On Debian possible default full paths are:

/usr/bin/ytasm - from package: yasm

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

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