IDMerger: 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

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/IDMerger - from package: topp

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