gtkada-config: 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/gtkada-config - from package: GtkAda-devel

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

On Debian possible default full paths are:

/usr/bin/gtkada-config - from package: libgtkada-bin

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

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