sort_files.inc: 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 Debian possible default full paths are:

/usr/share/ampache/www/bin/sort_files.inc - from package: ampache-common

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

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