asmerge: 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/asmerge - from package: libAfterImage-devel

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

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