tos-set-symbols: 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/tos-set-symbols - from package: tinyos-tools

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

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