structure-synth: 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/structure-synth - from package: structure-synth

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