tau_treemerge: 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/tau_treemerge - from package: tau

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

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