aim: 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
/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 Debian possible default full paths are:

/usr/bin/aim - from package: abinit

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