tree2leafnames: 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
/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/tree2leafnames - from package: prime-phylo

You may install the required package with command apt-get install {package}
Error in other languages:
tree2leafnames: bevel nie gevind nie
tree2leafnames: comandă negăsită
tree2leafnames: comando não encontrado
tree2leafnames: commande introuvable
tree2leafnames: command not found
tree2leafnames: käsku ei ole
tree2leafnames: không tìm thấy lệnh
tree2leafnames: komanda nerasta
tree2leafnames: Kommando nicht gefunden.
tree2leafnames: kommandot finns inte
tree2leafnames: komut yok
tree2leafnames: nie znaleziono polecenia
tree2leafnames: níor aimsíodh an t-ordú
tree2leafnames: no se encontró la orden
tree2leafnames: no s'ha trobat l'ordre
tree2leafnames: opdracht niet gevonden
tree2leafnames: parancs nem található
tree2leafnames: perintah tidak ditemukan
tree2leafnames: príkaz nenájdený
tree2leafnames: příkaz nenalezen
tree2leafnames: команда не найдена
tree2leafnames: командата не е открита
tree2leafnames: 命令找不到
tree2leafnames: コマンドが見つかりません