overlap: 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/lib/cmtk/bin/overlap - from package: cmtk

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

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