abc2abc: 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/bin/abc2abc - from package: abcmidi

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

Error in other languages:
abc2abc: bevel nie gevind nie
abc2abc: comandă negăsită
abc2abc: comando não encontrado
abc2abc: commande introuvable
abc2abc: command not found
abc2abc: käsku ei ole
abc2abc: không tìm thấy lệnh
abc2abc: komanda nerasta
abc2abc: Kommando nicht gefunden.
abc2abc: kommandot finns inte
abc2abc: komut yok
abc2abc: nie znaleziono polecenia
abc2abc: níor aimsíodh an t-ordú
abc2abc: no se encontró la orden
abc2abc: no s'ha trobat l'ordre
abc2abc: opdracht niet gevonden
abc2abc: parancs nem található
abc2abc: perintah tidak ditemukan
abc2abc: príkaz nenájdený
abc2abc: příkaz nenalezen
abc2abc: команда не найдена
abc2abc: командата не е открита
abc2abc: 命令找不到
abc2abc: コマンドが見つかりません