libast-config: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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 Debian possible default full paths are:

/usr/bin/libast-config - from package: libast2-dev

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