erlang_count: 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/erlang_count - from package: sloccount

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