aisexec: 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/sbin/aisexec - from package: openais

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

On Debian possible default full paths are:

/usr/sbin/aisexec - from package: openais

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

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